diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 89ce2d0..a836f5b 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -18,7 +18,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install pytest flake8 black
+        pip install black flake8 pytest
         pip install -r requirements.txt
         pip install .
     - name: Test with pytest
diff --git a/README.md b/README.md
index 6b2347e..213e570 100644
--- a/README.md
+++ b/README.md
@@ -81,7 +81,7 @@ The central feature of the project is Röntgen icon set. It is a set of monochro
 
 All icons tend to support common design style, which is heavily inspired by [Maki](https://github.com/mapbox/maki), [Osmic](https://github.com/gmgeo/osmic), and [Temaki](https://github.com/ideditor/temaki).
 
-Icons are used to visualize tags for nodes and areas. Unlike other renderers, Röntgen can use more than one icon to visualize an entity and use colors to visualize [`colour`](https://wiki.openstreetmap.org/wiki/Key:colour) value or other entity properties (like material or genus).
+Icons are used to visualize tags for nodes and areas. Unlike other renderers, Röntgen can use more than one icon to visualize an entity and use colors to visualize [`colour`](https://wiki.openstreetmap.org/wiki/Key:colour) value or other entity properties (like [`material`](https://wiki.openstreetmap.org/wiki/Key:material) or [`genus`](https://wiki.openstreetmap.org/wiki/Key:genus)).
 
 ![Icons](doc/grid.png)
 
@@ -217,7 +217,7 @@ Example:
 roentgen tile -b 2.361,48.871,2.368,48.875
 ```
 
-will generate 36 PNG tiles at scale 18 from tile 18/132791/90164 all the way to 18/132796/90169 and two cached files `cache/2.360,48.869,2.370,48.877.svg` and `cache/2.360,48.869,2.370,48.877.png`.
+will generate 36 PNG tiles at scale 18 from tile 18/132791/90164 all the way to 18/132796/90169 and two cached files `cache/2.360,48.869,2.370,48.877_18.svg` and `cache/2.360,48.869,2.370,48.877_18.png`.
 
 Tile server
 -----------
diff --git a/doc/readme.moi b/doc/readme.moi
index bd0a8c2..26f9878 100644
--- a/doc/readme.moi
+++ b/doc/readme.moi
@@ -4,7 +4,7 @@
 \b {Röntgen} (or \b {Roentgen} when ASCII is preferred) project consists of
 
 \list
-    {simple Python \ref {http://openstreetmap.org} {OpenStreetMap} renderer (see \ref {#usage} {usage}, \ref {#map-generation} {renderer documentation}),}
+    {simple Python \ref {http://openstreetmap.org} {OpenStreetMap} renderer and tile generator (see \ref {#usage-example} {usage}, \ref {#map-generation} {renderer documentation}, \ref {#tile-generation} {tile generation}),}
     {\ref {#icon-set} {set of CC-BY 4.0 icons} that can be used outside the project.}
 
 The idea behind the Röntgen project is to \b {show all the richness of the OpenStreetMap data}\: to have a possibility to \i {display any map feature} represented by OpenStreetMap data tags by means of colors, shapes, and icons.  Röntgen is created for OpenStreetMap contributors\: to display all changes one made on the map even if they are small, and for users\: to dig down into the map and find every detail that was mapped.
@@ -93,7 +93,7 @@ The central feature of the project is Röntgen icon set.  It is a set of monochr
 
 All icons tend to support common design style, which is heavily inspired by \ref {https://github.com/mapbox/maki} {Maki}, \ref {https://github.com/gmgeo/osmic} {Osmic}, and \ref {https://github.com/ideditor/temaki} {Temaki}.
 
-Icons are used to visualize tags for nodes and areas.  Unlike other renderers, Röntgen can use more than one icon to visualize an entity and use colors to visualize \osm {colour} value or other entity properties (like material or genus).
+Icons are used to visualize tags for nodes and areas.  Unlike other renderers, Röntgen can use more than one icon to visualize an entity and use colors to visualize \osm {colour} value or other entity properties (like \osm {material} or \osm {genus}).
 
 \image {doc/grid.png} {Icons}
 
@@ -230,7 +230,7 @@ Example\:
 
 \code {roentgen tile -b 2.361,48.871,2.368,48.875} {bash}
 
-will generate 36 PNG tiles at scale 18 from tile 18/132791/90164 all the way to 18/132796/90169 and two cached files \m {cache/2.360,48.869,2.370,48.877.svg} and \m {cache/2.360,48.869,2.370,48.877.png}.
+will generate 36 PNG tiles at scale 18 from tile 18/132791/90164 all the way to 18/132796/90169 and two cached files \m {cache/2.360,48.869,2.370,48.877_18.svg} and \m {cache/2.360,48.869,2.370,48.877_18.png}.
 
 \2 {Tile server} {tile-server}
 
diff --git a/roentgen/boundary_box.py b/roentgen/boundary_box.py
index 2342777..9a9d581 100644
--- a/roentgen/boundary_box.py
+++ b/roentgen/boundary_box.py
@@ -1,3 +1,6 @@
+"""
+Rectangle that limit space on the map.
+"""
 import logging
 import re
 from dataclasses import dataclass
diff --git a/roentgen/constructor.py b/roentgen/constructor.py
index 5cf441b..1aff9ea 100644
--- a/roentgen/constructor.py
+++ b/roentgen/constructor.py
@@ -21,7 +21,7 @@ from roentgen.icon import (
 from roentgen.osm_reader import OSMData, OSMNode, OSMRelation, OSMWay
 from roentgen.point import Point
 from roentgen.scheme import DEFAULT_COLOR, LineStyle, Scheme
-from roentgen.ui import AUTHOR_MODE, TIME_MODE
+from roentgen.ui import AUTHOR_MODE, BuildingMode, TIME_MODE
 from roentgen.util import MinMax
 
 # fmt: on
@@ -129,17 +129,25 @@ class Constructor:
         flinger: Flinger,
         scheme: Scheme,
         icon_extractor: ShapeExtractor,
-        check_level=lambda x: True,
-        mode: str = "normal",
-        seed: str = "",
+        options,
     ) -> None:
-        self.check_level = check_level
-        self.mode: str = mode
-        self.seed: str = seed
         self.osm_data: OSMData = osm_data
         self.flinger: Flinger = flinger
         self.scheme: Scheme = scheme
         self.icon_extractor = icon_extractor
+        self.options = options
+
+        if options.level:
+            if options.level == "overground":
+                self.check_level = check_level_overground
+            elif options.level == "underground":
+                self.check_level = lambda x: not check_level_overground(x)
+            else:
+                self.check_level = lambda x: not check_level_number(
+                    x, float(options.level)
+                )
+        else:
+            self.check_level = lambda x: True
 
         self.points: list[Point] = []
         self.figures: list[StyledFigure] = []
@@ -195,10 +203,10 @@ class Constructor:
             return
 
         center_point, center_coordinates = line_center(outers[0], self.flinger)
-        if self.mode in [AUTHOR_MODE, TIME_MODE]:
+        if self.options.mode in [AUTHOR_MODE, TIME_MODE]:
             color: Color
-            if self.mode == AUTHOR_MODE:
-                color = get_user_color(line.user, self.seed)
+            if self.options.mode == AUTHOR_MODE:
+                color = get_user_color(line.user, self.options.seed)
             else:  # self.mode == TIME_MODE
                 color = get_time_color(line.timestamp, self.osm_data.time)
             self.draw_special_mode(inners, line, outers, color)
@@ -207,7 +215,11 @@ class Constructor:
         if not line.tags:
             return
 
-        if "building:part" in line.tags or "building" in line.tags:
+        building_mode: BuildingMode = BuildingMode(self.options.buildings)
+        if "building" in line.tags or (
+            building_mode == BuildingMode.ISOMETRIC
+            and "building:part" in line.tags
+        ):
             self.add_building(
                 Building(line.tags, inners, outers, self.flinger, self.scheme)
             )
@@ -276,9 +288,7 @@ class Constructor:
             self.points.append(point)
 
     def draw_special_mode(self, inners, line, outers, color) -> None:
-        """
-        Add figure for special mode: time or author.
-        """
+        """Add figure for special mode: time or author."""
         style: dict[str, Any] = {
             "fill": "none",
             "stroke": color.hex,
@@ -289,9 +299,7 @@ class Constructor:
         )
 
     def construct_relations(self) -> None:
-        """
-        Construct Röntgen ways from OSM relations.
-        """
+        """Construct Röntgen ways from OSM relations."""
         for relation_id in self.osm_data.relations:
             relation: OSMRelation = self.osm_data.relations[relation_id]
             tags = relation.tags
@@ -344,13 +352,13 @@ class Constructor:
         icon_set: IconSet
         draw_outline: bool = True
 
-        if self.mode in [TIME_MODE, AUTHOR_MODE]:
+        if self.options.mode in [TIME_MODE, AUTHOR_MODE]:
             if not tags:
                 return
             color: Color = DEFAULT_COLOR
-            if self.mode == AUTHOR_MODE:
-                color = get_user_color(node.user, self.seed)
-            if self.mode == TIME_MODE:
+            if self.options.mode == AUTHOR_MODE:
+                color = get_user_color(node.user, self.options.seed)
+            if self.options.mode == TIME_MODE:
                 color = get_time_color(node.timestamp, self.osm_data.time)
             dot = self.icon_extractor.get_shape(DEFAULT_SMALL_SHAPE_ID)
             icon_set = IconSet(
@@ -382,3 +390,37 @@ class Constructor:
             priority=priority, draw_outline=draw_outline
         )  # fmt: skip
         self.points.append(point)
+
+
+def check_level_number(tags: dict[str, Any], level: float):
+    """Check if element described by tags is no the specified level."""
+    if "level" in tags:
+        levels = map(float, tags["level"].replace(",", ".").split(";"))
+        if level not in levels:
+            return False
+    else:
+        return False
+    return True
+
+
+def check_level_overground(tags: dict[str, Any]) -> bool:
+    """Check if element described by tags is overground."""
+    if "level" in tags:
+        try:
+            levels = map(float, tags["level"].replace(",", ".").split(";"))
+            for level in levels:
+                if level <= 0:
+                    return False
+        except ValueError:
+            pass
+    if "layer" in tags:
+        try:
+            levels = map(float, tags["layer"].replace(",", ".").split(";"))
+            for level in levels:
+                if level <= 0:
+                    return False
+        except ValueError:
+            pass
+    if "parking" in tags and tags["parking"] == "underground":
+        return False
+    return True
diff --git a/roentgen/direction.py b/roentgen/direction.py
index 8117d5f..67d18fb 100644
--- a/roentgen/direction.py
+++ b/roentgen/direction.py
@@ -17,9 +17,7 @@ DEFAULT_ANGLE: float = np.pi / 30
 
 
 def degree_to_radian(degree: float) -> float:
-    """
-    Convert value in degrees to radians.
-    """
+    """Convert value in degrees to radians."""
     return degree / 180 * np.pi
 
 
diff --git a/roentgen/element.py b/roentgen/element.py
index 05b0aa9..99b1a60 100644
--- a/roentgen/element.py
+++ b/roentgen/element.py
@@ -1,3 +1,6 @@
+"""
+Drawing separate map elements.
+"""
 import logging
 import sys
 from pathlib import Path
@@ -5,10 +8,10 @@ from pathlib import Path
 import numpy as np
 import svgwrite
 
-from roentgen.workspace import workspace
 from roentgen.icon import ShapeExtractor
 from roentgen.point import Point
 from roentgen.scheme import LineStyle, Scheme
+from roentgen.workspace import workspace
 
 
 def draw_element(options) -> None:
diff --git a/roentgen/figure.py b/roentgen/figure.py
index c599263..69930a2 100644
--- a/roentgen/figure.py
+++ b/roentgen/figure.py
@@ -109,6 +109,13 @@ class Building(Figure):
         if height:
             self.min_height = height
 
+    def draw(self, svg: Drawing, flinger: Flinger):
+        """Draw simple building shape."""
+        path: Path = Path(d=self.get_path(flinger))
+        path.update(self.line_style.style)
+        path.update({"stroke-linejoin": "round"})
+        svg.add(path)
+
     def draw_shade(self, building_shade, flinger: Flinger) -> None:
         """Draw shade casted by the building."""
         scale: float = flinger.get_scale() / 3.0
diff --git a/roentgen/flinger.py b/roentgen/flinger.py
index 208335b..bfe5b21 100644
--- a/roentgen/flinger.py
+++ b/roentgen/flinger.py
@@ -5,7 +5,7 @@ from typing import Optional
 
 import numpy as np
 
-from roentgen.util import MinMax
+from roentgen.boundary_box import BoundaryBox
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
@@ -45,7 +45,7 @@ class Flinger:
 
     def __init__(
         self,
-        geo_boundaries: MinMax,
+        geo_boundaries: BoundaryBox,
         scale: float = 18,
         border: np.array = np.array((0, 0)),
     ) -> None:
@@ -53,14 +53,14 @@ class Flinger:
         :param geo_boundaries: minimum and maximum latitude and longitude
         :param scale: OSM zoom level
         """
-        self.geo_boundaries: MinMax = geo_boundaries
+        self.geo_boundaries: BoundaryBox = geo_boundaries
         self.border = border
         self.ratio: float = (
             osm_zoom_level_to_pixels_per_meter(scale) * EQUATOR_LENGTH / 360
         )
         self.size: np.array = border * 2 + self.ratio * (
-            pseudo_mercator(self.geo_boundaries.max_)
-            - pseudo_mercator(self.geo_boundaries.min_)
+            pseudo_mercator(self.geo_boundaries.max_())
+            - pseudo_mercator(self.geo_boundaries.min_())
         )
         self.pixels_per_meter = osm_zoom_level_to_pixels_per_meter(scale)
 
@@ -74,7 +74,7 @@ class Flinger:
         """
         result: np.array = self.border + self.ratio * (
             pseudo_mercator(coordinates)
-            - pseudo_mercator(self.geo_boundaries.min_)
+            - pseudo_mercator(self.geo_boundaries.min_())
         )
 
         # Invert y axis on coordinate plane.
diff --git a/roentgen/grid.py b/roentgen/grid.py
index 78282f5..8d55018 100644
--- a/roentgen/grid.py
+++ b/roentgen/grid.py
@@ -48,9 +48,7 @@ class IconCollection:
         icons: list[Icon] = []
 
         def add() -> Icon:
-            """
-            Construct icon and add it to the list.
-            """
+            """Construct icon and add it to the list."""
             specifications = [
                 ShapeSpecification.from_structure(x, extractor, scheme)
                 for x in current_set
diff --git a/roentgen/icon.py b/roentgen/icon.py
index aeae595..7a6246e 100644
--- a/roentgen/icon.py
+++ b/roentgen/icon.py
@@ -118,9 +118,7 @@ class Shape:
 
 
 def parse_length(text: str) -> float:
-    """
-    Parse length from SVG attribute.
-    """
+    """Parse length from SVG attribute."""
     if text.endswith("px"):
         text = text[:-2]
     return float(text)
@@ -319,9 +317,7 @@ class ShapeSpecification:
         )
 
     def is_default(self) -> bool:
-        """
-        Check whether shape is default.
-        """
+        """Check whether shape is default."""
         return self.shape.id_ == DEFAULT_SHAPE_ID
 
     def draw(
@@ -389,15 +385,11 @@ class Icon:
     shape_specifications: list[ShapeSpecification]
 
     def get_shape_ids(self) -> list[str]:
-        """
-        Get all shape identifiers in the icon.
-        """
+        """Get all shape identifiers in the icon."""
         return [x.shape.id_ for x in self.shape_specifications]
 
     def get_names(self) -> list[str]:
-        """
-        Gat all shape names in the icon.
-        """
+        """Get all shape names in the icon."""
         return [
             (x.shape.name if x.shape.name else "unknown")
             for x in self.shape_specifications
@@ -462,15 +454,11 @@ class Icon:
             svg.write(output_file)
 
     def is_default(self) -> bool:
-        """
-        Check whether first shape is default.
-        """
+        """Check whether first shape is default."""
         return self.shape_specifications[0].is_default()
 
     def recolor(self, color: Color, white: Optional[Color] = None) -> None:
-        """
-        Paint all shapes in the color.
-        """
+        """Paint all shapes in the color."""
         for shape_specification in self.shape_specifications:
             if shape_specification.color == Color("white") and white:
                 shape_specification.color = white
@@ -480,9 +468,7 @@ class Icon:
     def add_specifications(
         self, specifications: list[ShapeSpecification]
     ) -> None:
-        """
-        Add shape specifications to the icon.
-        """
+        """Add shape specifications to the icon."""
         self.shape_specifications += specifications
 
     def __eq__(self, other) -> bool:
diff --git a/roentgen/main.py b/roentgen/main.py
index 2064738..80829b6 100644
--- a/roentgen/main.py
+++ b/roentgen/main.py
@@ -1,23 +1,16 @@
 """
 Röntgen entry point.
-
-Author: Sergey Vartanov (me@enzet.ru).
 """
 import argparse
 import logging
 import sys
 from pathlib import Path
 
-from roentgen.element import draw_element
-from roentgen.grid import draw_icons
-from roentgen.scheme import Scheme
 from roentgen.ui import parse_options
 from roentgen.workspace import Workspace
 
-
-def init_scheme(workspace: Workspace) -> Scheme:
-    """Initialize default scheme."""
-    return Scheme(workspace.DEFAULT_SCHEME_PATH)
+__author__ = "Sergey Vartanov"
+__email__ = "me@enzet.ru"
 
 
 def main() -> None:
@@ -38,6 +31,8 @@ def main() -> None:
         tile.ui(arguments)
 
     elif arguments.command == "icons":
+        from roentgen.grid import draw_icons
+
         draw_icons()
 
     elif arguments.command == "mapcss":
@@ -46,6 +41,8 @@ def main() -> None:
         mapcss.ui(arguments)
 
     elif arguments.command == "element":
+        from roentgen.element import draw_element
+
         draw_element(arguments)
 
     elif arguments.command == "server":
@@ -54,9 +51,10 @@ def main() -> None:
         server.ui(arguments)
 
     elif arguments.command == "taginfo":
+        from roentgen.scheme import Scheme
         from roentgen.taginfo import write_taginfo_project_file
 
-        write_taginfo_project_file(init_scheme(workspace))
+        write_taginfo_project_file(Scheme(workspace.DEFAULT_SCHEME_PATH))
 
 
 if __name__ == "__main__":
diff --git a/roentgen/mapcss.py b/roentgen/mapcss.py
index 5e410f6..5b8c320 100644
--- a/roentgen/mapcss.py
+++ b/roentgen/mapcss.py
@@ -140,9 +140,7 @@ class MapCSSWriter:
         return selector
 
     def write(self, output_file: TextIO) -> None:
-        """
-        Construct icon selectors for MapCSS 0.2 scheme.
-        """
+        """Construct icon selectors for MapCSS 0.2 scheme."""
         output_file.write(HEADER + "\n\n")
 
         if self.add_ways:
@@ -178,9 +176,7 @@ class MapCSSWriter:
 
 
 def ui(options) -> None:
-    """
-    Write MapCSS 0.2 scheme.
-    """
+    """Write MapCSS 0.2 scheme."""
     directory: Path = workspace.get_mapcss_path()
     icons_with_outline_path: Path = workspace.get_mapcss_icons_path()
 
diff --git a/roentgen/mapper.py b/roentgen/mapper.py
index ff02605..6dee615 100644
--- a/roentgen/mapper.py
+++ b/roentgen/mapper.py
@@ -1,10 +1,10 @@
 """
 Simple OpenStreetMap renderer.
 """
+import logging
 from pathlib import Path
 from typing import Any, Iterator
 
-import logging
 import numpy as np
 import svgwrite
 from colour import Color
@@ -12,17 +12,17 @@ from svgwrite.container import Group
 from svgwrite.path import Path as SVGPath
 from svgwrite.shapes import Rect
 
-from roentgen.icon import ShapeExtractor
-from roentgen.osm_getter import NetworkError, get_osm
+from roentgen.boundary_box import BoundaryBox
 from roentgen.constructor import Constructor
 from roentgen.figure import Road
 from roentgen.flinger import Flinger
+from roentgen.icon import ShapeExtractor
+from roentgen.osm_getter import NetworkError, get_osm
 from roentgen.osm_reader import OSMData, OSMNode, OSMReader, OverpassReader
 from roentgen.point import Occupied
 from roentgen.road import Intersection, RoadPart
 from roentgen.scheme import Scheme
-from roentgen.ui import AUTHOR_MODE, BoundaryBox, TIME_MODE, progress_bar
-from roentgen.util import MinMax
+from roentgen.ui import AUTHOR_MODE, BuildingMode, TIME_MODE, progress_bar
 from roentgen.workspace import workspace
 
 __author__ = "Sergey Vartanov"
@@ -35,24 +35,15 @@ class Map:
     """
 
     def __init__(
-        self,
-        flinger: Flinger,
-        svg: svgwrite.Drawing,
-        scheme: Scheme,
-        overlap: int = 12,
-        mode: str = "normal",
-        label_mode: str = "main",
+        self, flinger: Flinger, svg: svgwrite.Drawing, scheme: Scheme, options
     ) -> None:
-        self.overlap: int = overlap
-        self.mode: str = mode
-        self.label_mode: str = label_mode
-
         self.flinger: Flinger = flinger
         self.svg: svgwrite.Drawing = svg
         self.scheme: Scheme = scheme
+        self.options = options
 
         self.background_color: Color = self.scheme.get_color("background_color")
-        if self.mode in [AUTHOR_MODE, TIME_MODE]:
+        if self.options.mode in [AUTHOR_MODE, TIME_MODE]:
             self.background_color: Color = Color("#111111")
 
     def draw(self, constructor: Constructor) -> None:
@@ -89,11 +80,11 @@ class Map:
 
         # All other points
 
-        if self.overlap == 0:
+        if self.options.overlap == 0:
             occupied = None
         else:
             occupied = Occupied(
-                self.flinger.size[0], self.flinger.size[1], self.overlap
+                self.flinger.size[0], self.flinger.size[1], self.options.overlap
             )
 
         nodes = sorted(constructor.points, key=lambda x: -x.priority)
@@ -114,17 +105,24 @@ class Map:
                 steps * 2 + index, steps * 3, step=10, text="Drawing texts"
             )
             if (
-                self.mode not in [TIME_MODE, AUTHOR_MODE]
-                and self.label_mode != "no"
+                self.options.mode not in [TIME_MODE, AUTHOR_MODE]
+                and self.options.label_mode != "no"
             ):
-                point.draw_texts(self.svg, occupied, self.label_mode)
+                point.draw_texts(self.svg, occupied, self.options.label_mode)
 
         progress_bar(-1, len(nodes), step=10, text="Drawing nodes")
 
     def draw_buildings(self, constructor: Constructor) -> None:
         """Draw buildings: shade, walls, and roof."""
-        building_shade: Group = Group(opacity=0.1)
+        building_mode: BuildingMode = BuildingMode(self.options.buildings)
+
+        if building_mode == BuildingMode.FLAT:
+            for building in constructor.buildings:
+                building.draw(self.svg, self.flinger)
+            return
+
         scale: float = self.flinger.get_scale() / 3.0
+        building_shade: Group = Group(opacity=0.1)
         for building in constructor.buildings:
             building.draw_shade(building_shade, self.flinger)
         self.svg.add(building_shade)
@@ -150,9 +148,7 @@ class Map:
     def draw_road(
         self, road: Road, color: Color, extra_width: float = 0
     ) -> None:
-        """
-        Draw road as simple SVG path.
-        """
+        """Draw road as simple SVG path."""
         self.flinger.get_scale()
         if road.width is not None:
             width = road.width
@@ -172,9 +168,7 @@ class Map:
         self.svg.add(path)
 
     def draw_roads(self, roads: Iterator[Road]) -> None:
-        """
-        Draw road as simple SVG path.
-        """
+        """Draw road as simple SVG path."""
         nodes: dict[OSMNode, set[RoadPart]] = {}
 
         for road in roads:
@@ -203,44 +197,6 @@ class Map:
             intersection.draw(self.svg, True)
 
 
-def check_level_number(tags: dict[str, Any], level: float):
-    """
-    Check if element described by tags is no the specified level.
-    """
-    if "level" in tags:
-        levels = map(float, tags["level"].replace(",", ".").split(";"))
-        if level not in levels:
-            return False
-    else:
-        return False
-    return True
-
-
-def check_level_overground(tags: dict[str, Any]) -> bool:
-    """
-    Check if element described by tags is overground.
-    """
-    if "level" in tags:
-        try:
-            levels = map(float, tags["level"].replace(",", ".").split(";"))
-            for level in levels:
-                if level <= 0:
-                    return False
-        except ValueError:
-            pass
-    if "layer" in tags:
-        try:
-            levels = map(float, tags["layer"].replace(",", ".").split(";"))
-            for level in levels:
-                if level <= 0:
-                    return False
-        except ValueError:
-            pass
-    if "parking" in tags and tags["parking"] == "underground":
-        return False
-    return True
-
-
 def ui(options) -> None:
     """
     Röntgen entry point.
@@ -276,27 +232,21 @@ def ui(options) -> None:
     min_: np.array
     max_: np.array
     osm_data: OSMData
+    view_box: BoundaryBox
 
     if input_file_names[0].name.endswith(".json"):
         reader: OverpassReader = OverpassReader()
         reader.parse_json_file(input_file_names[0])
 
         osm_data = reader.osm_data
-        view_box = MinMax(
-            np.array(
-                (osm_data.boundary_box[0].min_, osm_data.boundary_box[1].min_)
-            ),
-            np.array(
-                (osm_data.boundary_box[0].max_, osm_data.boundary_box[1].max_)
-            ),
-        )
+        view_box = boundary_box
     else:
         is_full: bool = options.mode in [AUTHOR_MODE, TIME_MODE]
         osm_reader = OSMReader(is_full=is_full)
 
         for file_name in input_file_names:
             if not file_name.is_file():
-                print(f"Fatal: no such file: {file_name}.")
+                logging.fatal(f"No such file: {file_name}.")
                 exit(1)
 
             osm_reader.parse_osm_file(file_name)
@@ -304,10 +254,7 @@ def ui(options) -> None:
         osm_data = osm_reader.osm_data
 
         if options.boundary_box:
-            view_box = MinMax(
-                np.array((boundary_box.bottom, boundary_box.left)),
-                np.array((boundary_box.top, boundary_box.right)),
-            )
+            view_box = boundary_box
         else:
             view_box = osm_data.view_box
 
@@ -321,48 +268,18 @@ def ui(options) -> None:
         workspace.ICONS_PATH, workspace.ICONS_CONFIG_PATH
     )
 
-    if options.level:
-        if options.level == "overground":
-            check_level = check_level_overground
-        elif options.level == "underground":
-
-            def check_level(x) -> bool:
-                """Draw underground objects."""
-                return not check_level_overground(x)
-
-        else:
-
-            def check_level(x) -> bool:
-                """Draw objects on the specified level."""
-                return not check_level_number(x, float(options.level))
-
-    else:
-
-        def check_level(_) -> bool:
-            """Draw objects on any level."""
-            return True
-
     constructor: Constructor = Constructor(
-        osm_data,
-        flinger,
-        scheme,
-        icon_extractor,
-        check_level,
-        options.mode,
-        options.seed,
+        osm_data=osm_data,
+        flinger=flinger,
+        scheme=scheme,
+        icon_extractor=icon_extractor,
+        options=options,
     )
     constructor.construct()
 
-    painter: Map = Map(
-        overlap=options.overlap,
-        mode=options.mode,
-        label_mode=options.label_mode,
-        flinger=flinger,
-        svg=svg,
-        scheme=scheme,
-    )
+    painter: Map = Map(flinger=flinger, svg=svg, scheme=scheme, options=options)
     painter.draw(constructor)
 
-    print(f"Writing output SVG to {options.output_file_name}...")
+    logging.info(f"Writing output SVG to {options.output_file_name}...")
     with open(options.output_file_name, "w") as output_file:
         svg.write(output_file)
diff --git a/roentgen/osm_getter.py b/roentgen/osm_getter.py
index 955839d..3d7d701 100644
--- a/roentgen/osm_getter.py
+++ b/roentgen/osm_getter.py
@@ -9,7 +9,7 @@ from pathlib import Path
 
 import urllib3
 
-from roentgen.ui import BoundaryBox
+from roentgen.boundary_box import BoundaryBox
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
diff --git a/roentgen/osm_reader.py b/roentgen/osm_reader.py
index 34354a0..fbd034b 100644
--- a/roentgen/osm_reader.py
+++ b/roentgen/osm_reader.py
@@ -11,6 +11,7 @@ from xml.etree import ElementTree
 
 import numpy as np
 
+from roentgen.boundary_box import BoundaryBox
 from roentgen.util import MinMax
 
 __author__ = "Sergey Vartanov"
@@ -37,9 +38,7 @@ STAGES_OF_DECAY: list[str] = [
 
 
 def parse_float(string: str) -> Optional[float]:
-    """
-    Parse string representation of a float or integer value.
-    """
+    """Parse string representation of a float or integer value."""
     try:
         return float(string)
     except (TypeError, ValueError):
@@ -108,7 +107,7 @@ class OSMNode(Tagged):
         super().__init__()
 
         self.id_: Optional[int] = None
-        self.coordinates: Optional[np.array] = None
+        self.coordinates: Optional[np.ndarray] = None
 
         self.visible: Optional[str] = None
         self.changeset: Optional[str] = None
@@ -118,10 +117,8 @@ class OSMNode(Tagged):
 
     @classmethod
     def from_xml_structure(cls, element, is_full: bool = False) -> "OSMNode":
-        """
-        Parse node from OSM XML `<node>` element.
-        """
-        node = cls()
+        """Parse node from OSM XML `<node>` element."""
+        node: "OSMNode" = cls()
         attributes = element.attrib
         node.id_ = int(attributes["id"])
         node.coordinates = np.array(
@@ -178,9 +175,7 @@ class OSMWay(Tagged):
 
     @classmethod
     def from_xml_structure(cls, element, nodes, is_full: bool) -> "OSMWay":
-        """
-        Parse way from OSM XML `<way>` element.
-        """
+        """Parse way from OSM XML `<way>` element."""
         way = cls(int(element.attrib["id"]))
         if is_full:
             way.visible = element.attrib["visible"]
@@ -215,15 +210,11 @@ class OSMWay(Tagged):
         return self
 
     def is_cycle(self) -> bool:
-        """
-        Is way a cycle way or an area boundary.
-        """
+        """Is way a cycle way or an area boundary."""
         return self.nodes[0] == self.nodes[-1]
 
     def try_to_glue(self, other: "OSMWay") -> Optional["OSMWay"]:
-        """
-        Create new combined way if ways share endpoints.
-        """
+        """Create new combined way if ways share endpoints."""
         if self.nodes[0] == other.nodes[0]:
             return OSMWay(nodes=list(reversed(other.nodes[1:])) + self.nodes)
         if self.nodes[0] == other.nodes[-1]:
@@ -255,9 +246,7 @@ class OSMRelation(Tagged):
 
     @classmethod
     def from_xml_structure(cls, element, is_full: bool) -> "OSMRelation":
-        """
-        Parse relation from OSM XML `<relation>` element.
-        """
+        """Parse relation from OSM XML `<relation>` element."""
         attributes = element.attrib
         relation = cls(int(attributes["id"]))
         if is_full:
@@ -321,33 +310,24 @@ class OSMData:
 
         self.authors: set[str] = set()
         self.time: MinMax = MinMax()
-        self.boundary_box: list[MinMax] = [MinMax(), MinMax()]
-        self.view_box = None
+        self.view_box: Optional[BoundaryBox] = None
 
     def add_node(self, node: OSMNode) -> None:
-        """
-        Add node and update map parameters.
-        """
+        """Add node and update map parameters."""
         self.nodes[node.id_] = node
         if node.user:
             self.authors.add(node.user)
         self.time.update(node.timestamp)
-        self.boundary_box[0].update(node.coordinates[0])
-        self.boundary_box[1].update(node.coordinates[1])
 
     def add_way(self, way: OSMWay) -> None:
-        """
-        Add way and update map parameters.
-        """
+        """Add way and update map parameters."""
         self.ways[way.id_] = way
         if way.user:
             self.authors.add(way.user)
         self.time.update(way.timestamp)
 
     def add_relation(self, relation: OSMRelation) -> None:
-        """
-        Add relation and update map parameters.
-        """
+        """Add relation and update map parameters."""
         self.relations[relation.id_] = relation
 
 
@@ -362,9 +342,7 @@ class OverpassReader:
         self.osm_data = OSMData()
 
     def parse_json_file(self, file_name: Path) -> OSMData:
-        """
-        Parse JSON structure from the file and construct map.
-        """
+        """Parse JSON structure from the file and construct map."""
         with file_name.open() as input_file:
             structure = json.load(input_file)
 
@@ -460,15 +438,11 @@ class OSMReader:
         return self.osm_data
 
     def parse_bounds(self, element) -> None:
-        """
-        Parse view box from XML element.
-        """
+        """Parse view box from XML element."""
         attributes = element.attrib
-        self.osm_data.view_box = MinMax(
-            np.array(
-                (float(attributes["minlat"]), float(attributes["minlon"]))
-            ),
-            np.array(
-                (float(attributes["maxlat"]), float(attributes["maxlon"]))
-            ),
+        self.osm_data.view_box = BoundaryBox(
+            float(attributes["minlon"]),
+            float(attributes["minlat"]),
+            float(attributes["maxlon"]),
+            float(attributes["maxlat"]),
         )
diff --git a/roentgen/point.py b/roentgen/point.py
index ab8402f..83983cb 100644
--- a/roentgen/point.py
+++ b/roentgen/point.py
@@ -30,17 +30,13 @@ class Occupied:
         self.overlap: float = overlap
 
     def check(self, point: np.array) -> bool:
-        """
-        Check whether point is already occupied by other elements.
-        """
+        """Check whether point is already occupied by other elements."""
         if 0 <= point[0] < self.width and 0 <= point[1] < self.height:
             return self.matrix[point[0], point[1]]
         return True
 
     def register(self, point) -> None:
-        """
-        Register that point is occupied by an element.
-        """
+        """Register that point is occupied by an element."""
         if 0 <= point[0] < self.width and 0 <= point[1] < self.height:
             self.matrix[point[0], point[1]] = True
             assert self.matrix[point[0], point[1]]
@@ -86,9 +82,7 @@ class Point(Tagged):
     def draw_main_shapes(
         self, svg: svgwrite.Drawing, occupied: Optional[Occupied] = None
     ) -> None:
-        """
-        Draw main shape for one node.
-        """
+        """Draw main shape for one node."""
         keys_left = [x for x in self.tags.keys() if x not in self.processed]
         if (
             self.icon_set.main_icon.is_default()
@@ -107,9 +101,7 @@ class Point(Tagged):
     def draw_extra_shapes(
         self, svg: svgwrite.Drawing, occupied: Optional[Occupied] = None
     ) -> None:
-        """
-        Draw secondary shapes.
-        """
+        """Draw secondary shapes."""
         if not self.icon_set.extra_icons or not self.main_icon_painted:
             return
 
@@ -141,9 +133,7 @@ class Point(Tagged):
         occupied,
         tags: Optional[dict[str, str]] = None,
     ) -> bool:
-        """
-        Draw one combined icon and its outline.
-        """
+        """Draw one combined icon and its outline."""
         # Down-cast floats to integers to make icons pixel-perfect.
         position = list(map(int, position))
 
@@ -173,9 +163,7 @@ class Point(Tagged):
         occupied: Optional[Occupied] = None,
         label_mode: str = "main",
     ) -> None:
-        """
-        Draw all labels.
-        """
+        """Draw all labels."""
         labels: list[Label]
 
         if label_mode == "main":
diff --git a/roentgen/road.py b/roentgen/road.py
index 2afa735..6bcef58 100644
--- a/roentgen/road.py
+++ b/roentgen/road.py
@@ -81,14 +81,13 @@ class RoadPart:
         self.left_outer = None
         self.right_outer = None
         self.point_a = None
+        self.point_middle = None
 
     @classmethod
     def from_nodes(
         cls, node_1: OSMNode, node_2: OSMNode, flinger: Flinger, road, scale
     ) -> "RoadPart":
-        """
-        Construct road part from OSM nodes.
-        """
+        """Construct road part from OSM nodes."""
         lanes = [Lane(road.width / road.lanes)] * road.lanes
 
         return cls(
@@ -99,9 +98,7 @@ class RoadPart:
         )
 
     def update(self) -> None:
-        """
-        Compute additional points.
-        """
+        """Compute additional points."""
         if self.left_connection is not None:
             self.right_projection = (
                 self.left_connection + self.right_vector - self.left_vector
@@ -136,15 +133,11 @@ class RoadPart:
                 self.point_a = self.point_middle
 
     def get_angle(self) -> float:
-        """
-        Get an angle between line and x axis.
-        """
+        """Get an angle between line and x axis."""
         return compute_angle(self.point_2 - self.point_1)
 
     def draw_normal(self, drawing: svgwrite.Drawing):
-        """
-        Draw some debug lines.
-        """
+        """Draw some debug lines."""
         line = drawing.path(
             ("M", self.point_1, "L", self.point_2),
             fill="none",
@@ -154,9 +147,7 @@ class RoadPart:
         drawing.add(line)
 
     def draw_debug(self, drawing: svgwrite.Drawing):
-        """
-        Draw some debug lines.
-        """
+        """Draw some debug lines."""
         line = drawing.path(
             ("M", self.point_1, "L", self.point_2),
             fill="none",
@@ -237,9 +228,7 @@ class RoadPart:
         # self.draw_entrance(drawing, True)
 
     def draw(self, drawing: svgwrite.Drawing):
-        """
-        Draw road part.
-        """
+        """Draw road part."""
         if self.left_connection is not None:
             path_commands = [
                 "M", self.point_2 + self.right_vector,
@@ -251,9 +240,7 @@ class RoadPart:
             drawing.add(drawing.path(path_commands, fill="#CCCCCC"))
 
     def draw_entrance(self, drawing: svgwrite.Drawing, is_debug: bool = False):
-        """
-        Draw intersection entrance part.
-        """
+        """Draw intersection entrance part."""
         if (
             self.left_connection is not None
             and self.right_connection is not None
@@ -277,9 +264,7 @@ class RoadPart:
                 drawing.add(drawing.path(path_commands, fill="#88FF88"))
 
     def draw_lanes(self, drawing: svgwrite.Drawing, scale: float):
-        """
-        Draw lane delimiters.
-        """
+        """Draw lane delimiters."""
         for lane in self.lanes:
             shift = self.right_vector - self.turned * lane.get_width(scale)
             path = drawing.path(
@@ -340,9 +325,7 @@ class Intersection:
             part_2.update()
 
     def draw(self, drawing: svgwrite.Drawing, is_debug: bool = False) -> None:
-        """
-        Draw all road parts and intersection.
-        """
+        """Draw all road parts and intersection."""
         inner_commands = ["M"]
         for part in self.parts:
             inner_commands += [part.left_connection, "L"]
diff --git a/roentgen/scheme.py b/roentgen/scheme.py
index b803cef..d564779 100644
--- a/roentgen/scheme.py
+++ b/roentgen/scheme.py
@@ -413,12 +413,6 @@ class Scheme:
         if main_icon and color:
             main_icon.recolor(color)
 
-        # keys_left = [
-        #     x
-        #     for x in tags.keys()
-        #     if x not in processed and not self.is_no_drawable(x)
-        # ]
-
         default_shape = extractor.get_shape(DEFAULT_SHAPE_ID)
         if not main_icon:
             main_icon = Icon([ShapeSpecification(default_shape)])
diff --git a/roentgen/server.py b/roentgen/server.py
index a421f32..182198b 100644
--- a/roentgen/server.py
+++ b/roentgen/server.py
@@ -1,5 +1,5 @@
 """
-Röntgen tile server for sloppy maps.
+Röntgen tile server for slippy maps.
 """
 import logging
 from http.server import HTTPServer, SimpleHTTPRequestHandler
@@ -15,13 +15,14 @@ __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
 
 
-class Handler(SimpleHTTPRequestHandler):
+class _Handler(SimpleHTTPRequestHandler):
     """
     HTTP request handler that process sloppy map tile requests.
     """
 
     cache: Path = Path("cache")
     update_cache: bool = False
+    options = None
 
     def __init__(
         self, request: bytes, client_address: tuple[str, int], server
@@ -33,22 +34,25 @@ class Handler(SimpleHTTPRequestHandler):
         parts: list[str] = self.path.split("/")
         if not (len(parts) == 5 and not parts[0] and parts[1] == "tiles"):
             return
-        zoom: int = int(parts[2])
+
+        scale: int = int(parts[2])
         x: int = int(parts[3])
         y: int = int(parts[4])
         tile_path: Path = workspace.get_tile_path()
-        png_path = tile_path / f"tile_{zoom}_{x}_{y}.png"
+        png_path: Path = tile_path / f"tile_{scale}_{x}_{y}.png"
+
         if self.update_cache:
-            svg_path = tile_path / f"tile_{zoom}_{x}_{y}.svg"
+            svg_path: Path = png_path.with_suffix(".svg")
             if not png_path.exists():
                 if not svg_path.exists():
-                    tile = Tile(x, y, zoom)
-                    tile.draw(tile_path, self.cache)
+                    tile = Tile(x, y, scale)
+                    tile.draw(tile_path, self.cache, self.options)
                 with svg_path.open() as input_file:
                     cairosvg.svg2png(
                         file_obj=input_file, write_to=str(png_path)
                     )
                 logging.info(f"SVG file is rasterized to {png_path}.")
+
         if png_path.exists():
             with png_path.open("rb") as input_file:
                 self.send_response(200)
@@ -63,11 +67,12 @@ def ui(options) -> None:
     server: Optional[HTTPServer] = None
     try:
         port: int = 8080
-        handler = Handler
+        handler = _Handler
         handler.cache = Path(options.cache)
+        handler.options = options
         server: HTTPServer = HTTPServer(("", port), handler)
-        server.serve_forever()
         logging.info(f"Server started on port {port}.")
+        server.serve_forever()
     finally:
         if server:
             server.socket.close()
diff --git a/roentgen/text.py b/roentgen/text.py
index d62ac7e..6a55ff3 100644
--- a/roentgen/text.py
+++ b/roentgen/text.py
@@ -75,16 +75,12 @@ def format_voltage(value: str) -> str:
 
 
 def format_frequency(value: str) -> str:
-    """
-    Format frequency value to more human-readable form.
-    """
+    """Format frequency value to more human-readable form."""
     return f"{value} "
 
 
 def get_text(tags: dict[str, Any], processed: set[str]) -> list[Label]:
-    """
-    Get text representation of writable tags.
-    """
+    """Get text representation of writable tags."""
     texts: list[Label] = []
     values: list[str] = []
 
diff --git a/roentgen/tile.py b/roentgen/tile.py
index 9a719a4..0460232 100644
--- a/roentgen/tile.py
+++ b/roentgen/tile.py
@@ -21,8 +21,7 @@ from roentgen.mapper import Map
 from roentgen.osm_getter import NetworkError, get_osm
 from roentgen.osm_reader import OSMData, OSMReader
 from roentgen.scheme import Scheme
-from roentgen.ui import BoundaryBox
-from roentgen.util import MinMax
+from roentgen.boundary_box import BoundaryBox
 from roentgen.workspace import workspace
 
 __author__ = "Sergey Vartanov"
@@ -116,36 +115,33 @@ class Tile:
             f"https://tile.openstreetmap.org/{self.scale}/{self.x}/{self.y}.png"
         )
 
-    def draw(self, directory_name: Path, cache_path: Path) -> None:
+    def draw(self, directory_name: Path, cache_path: Path, options) -> None:
         """
         Draw tile to SVG and PNG files.
 
         :param directory_name: output directory to storing tiles
         :param cache_path: directory to store SVG and PNG tiles
+        :param options: drawing configuration
         """
         try:
             osm_data: OSMData = self.load_osm_data(cache_path)
         except NetworkError as e:
             raise NetworkError(f"Map is not loaded. {e.message}")
 
-        self.draw_with_osm_data(osm_data, directory_name)
+        self.draw_with_osm_data(osm_data, directory_name, options)
 
     def draw_with_osm_data(
-        self, osm_data: OSMData, directory_name: Path
+        self, osm_data: OSMData, directory_name: Path, options
     ) -> None:
         """Draw SVG and PNG tile using OpenStreetMap data."""
-        latitude_1, longitude_1 = self.get_coordinates()
-        latitude_2, longitude_2 = Tile(
+        top, left = self.get_coordinates()
+        bottom, right = Tile(
             self.x + 1, self.y + 1, self.scale
         ).get_coordinates()
 
-        min_: np.array = np.array(
-            (min(latitude_1, latitude_2), min(longitude_1, longitude_2))
+        flinger: Flinger = Flinger(
+            BoundaryBox(left, bottom, right, top), self.scale
         )
-        max_: np.array = np.array(
-            (max(latitude_1, latitude_2), max(longitude_1, longitude_2))
-        )
-        flinger: Flinger = Flinger(MinMax(min_, max_), self.scale)
         size: np.array = flinger.size
 
         output_file_name: Path = self.get_file_name(directory_name)
@@ -158,11 +154,13 @@ class Tile:
         )
         scheme: Scheme = Scheme(workspace.DEFAULT_SCHEME_PATH)
         constructor: Constructor = Constructor(
-            osm_data, flinger, scheme, icon_extractor
+            osm_data, flinger, scheme, icon_extractor, options
         )
         constructor.construct()
 
-        painter: Map = Map(flinger=flinger, svg=svg, scheme=scheme)
+        painter: Map = Map(
+            flinger=flinger, svg=svg, scheme=scheme, options=options
+        )
         painter.draw(constructor)
 
         with output_file_name.open("w") as output_file:
@@ -217,13 +215,16 @@ class Tiles:
 
         return cls(tiles, tile_1, tile_2, scale, extended_boundary_box)
 
-    def draw_separately(self, directory: Path, cache_path: Path) -> None:
+    def draw_separately(
+        self, directory: Path, cache_path: Path, options
+    ) -> None:
         """
         Draw set of tiles as SVG file separately and rasterize them into a set
         of PNG files with cairosvg.
 
         :param directory: directory for tiles
         :param cache_path: directory for temporary OSM files
+        :param options: drawing configuration
         """
         cache_file_path: Path = (
             cache_path / f"{self.boundary_box.get_format()}.osm"
@@ -234,7 +235,7 @@ class Tiles:
         for tile in self.tiles:
             file_path: Path = tile.get_file_name(directory)
             if not file_path.exists():
-                tile.draw_with_osm_data(osm_data, directory)
+                tile.draw_with_osm_data(osm_data, directory, options)
             else:
                 logging.debug(f"File {file_path} already exists.")
 
@@ -252,18 +253,19 @@ class Tiles:
         """Check whether all tiles are drawn."""
         return all(x.exists(directory_name) for x in self.tiles)
 
-    def draw(self, directory: Path, cache_path: Path) -> None:
+    def draw(self, directory: Path, cache_path: Path, options) -> None:
         """
         Draw one PNG image with all tiles and split it into a set of separate
         PNG file with Pillow.
 
         :param directory: directory for tiles
         :param cache_path: directory for temporary OSM files
+        :param options: drawing configuration
         """
         if self.tiles_exist(directory):
             return
 
-        self.draw_image(cache_path)
+        self.draw_image(cache_path, options)
 
         input_path: Path = self.get_file_path(cache_path).with_suffix(".png")
         with input_path.open("rb") as input_file:
@@ -288,11 +290,12 @@ class Tiles:
         """Get path of the output SVG file."""
         return cache_path / f"{self.boundary_box.get_format()}_{self.scale}.svg"
 
-    def draw_image(self, cache_path: Path) -> None:
+    def draw_image(self, cache_path: Path, options) -> None:
         """
         Draw all tiles as one picture.
 
         :param cache_path: directory for temporary SVG file and OSM files
+        :param options: drawing configuration
         """
         output_path: Path = self.get_file_path(cache_path)
 
@@ -303,27 +306,29 @@ class Tiles:
             get_osm(self.boundary_box, cache_file_path)
 
             osm_data: OSMData = OSMReader().parse_osm_file(cache_file_path)
-            latitude_2, longitude_1 = self.tile_1.get_coordinates()
-            latitude_1, longitude_2 = Tile(
+            top, left = self.tile_1.get_coordinates()
+            bottom, right = Tile(
                 self.tile_2.x + 1, self.tile_2.y + 1, self.scale
             ).get_coordinates()
-            min_: np.ndarray = np.array((latitude_1, longitude_1))
-            max_: np.ndarray = np.array((latitude_2, longitude_2))
 
-            flinger: Flinger = Flinger(MinMax(min_, max_), self.scale)
+            flinger: Flinger = Flinger(
+                BoundaryBox(left, bottom, right, top), self.scale
+            )
             extractor: ShapeExtractor = ShapeExtractor(
                 workspace.ICONS_PATH, workspace.ICONS_CONFIG_PATH
             )
             scheme: Scheme = Scheme(workspace.DEFAULT_SCHEME_PATH)
             constructor: Constructor = Constructor(
-                osm_data, flinger, scheme, extractor
+                osm_data, flinger, scheme, extractor, options=options
             )
             constructor.construct()
 
             svg: svgwrite.Drawing = svgwrite.Drawing(
                 str(output_path), size=flinger.size
             )
-            map_: Map = Map(flinger=flinger, svg=svg, scheme=scheme)
+            map_: Map = Map(
+                flinger=flinger, svg=svg, scheme=scheme, options=options
+            )
             map_.draw(constructor)
 
             logging.info(f"Writing output SVG {output_path}...")
@@ -351,13 +356,13 @@ def ui(options) -> None:
         )
         tile: Tile = Tile.from_coordinates(np.array(coordinates), options.scale)
         try:
-            tile.draw(directory, Path(options.cache))
+            tile.draw(directory, Path(options.cache), options)
         except NetworkError as e:
             logging.fatal(e.message)
     elif options.tile:
         scale, x, y = map(int, options.tile.split("/"))
         tile: Tile = Tile(x, y, scale)
-        tile.draw(directory, Path(options.cache))
+        tile.draw(directory, Path(options.cache), options)
     elif options.boundary_box:
         boundary_box: Optional[BoundaryBox] = BoundaryBox.from_text(
             options.boundary_box
@@ -365,7 +370,7 @@ def ui(options) -> None:
         if boundary_box is None:
             sys.exit(1)
         tiles: Tiles = Tiles.from_boundary_box(boundary_box, options.scale)
-        tiles.draw(directory, Path(options.cache))
+        tiles.draw(directory, Path(options.cache), options)
     else:
         logging.fatal(
             "Specify either --coordinates, --boundary-box, or --tile."
diff --git a/roentgen/ui.py b/roentgen/ui.py
index 519678f..7011fe2 100644
--- a/roentgen/ui.py
+++ b/roentgen/ui.py
@@ -2,16 +2,12 @@
 Command-line user interface.
 """
 import argparse
-import re
 import sys
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
 
-import logging
-from dataclasses import dataclass
-
-import numpy as np
+from enum import Enum
 
 from roentgen.osm_reader import STAGES_OF_DECAY
 
@@ -21,8 +17,15 @@ BOXES_LENGTH: int = len(BOXES)
 AUTHOR_MODE: str = "author"
 TIME_MODE: str = "time"
 
-LATITUDE_MAX_DIFFERENCE: float = 0.5
-LONGITUDE_MAX_DIFFERENCE: float = 0.5
+
+class BuildingMode(Enum):
+    """
+    Building drawing mode.
+    """
+
+    FLAT = "flat"
+    ISOMETRIC = "isometric"
+    ISOMETRIC_NO_PARTS = "isometric-no-parts"
 
 
 def parse_options(args) -> argparse.Namespace:
@@ -32,8 +35,14 @@ def parse_options(args) -> argparse.Namespace:
     )
     subparser = parser.add_subparsers(dest="command")
 
-    add_render_arguments(subparser.add_parser("render"))
-    add_tile_arguments(subparser.add_parser("tile"))
+    tile_parser = subparser.add_parser("tile")
+    add_tile_arguments(tile_parser)
+    add_map_arguments(tile_parser)
+
+    render_parser = subparser.add_parser("render")
+    add_render_arguments(render_parser)
+    add_map_arguments(render_parser)
+
     add_server_arguments(subparser.add_parser("server"))
     add_element_arguments(subparser.add_parser("element"))
     add_mapcss_arguments(subparser.add_parser("mapcss"))
@@ -46,13 +55,36 @@ def parse_options(args) -> argparse.Namespace:
     return arguments
 
 
-def add_tile_arguments(parser: argparse.ArgumentParser) -> None:
-    """Add arguments for tile command."""
+def add_map_arguments(parser: argparse.ArgumentParser) -> None:
+    """Add map-specific arguments."""
     parser.add_argument(
-        "-c",
-        "--coordinates",
-        metavar="<latitude>,<longitude>",
-        help="coordinates of any location inside the tile",
+        "--buildings",
+        metavar="<mode>",
+        default="flat",
+        choices=(x.value for x in BuildingMode),
+        help="building drawing mode: "
+        + ", ".join(x.value for x in BuildingMode),
+    )
+    parser.add_argument(
+        "--mode",
+        default="normal",
+        help="map drawing mode",
+        metavar="<string>",
+    )
+    parser.add_argument(
+        "--overlap",
+        dest="overlap",
+        default=12,
+        type=int,
+        help="how many pixels should be left around icons and text",
+        metavar="<integer>",
+    )
+    parser.add_argument(
+        "--labels",
+        help="label drawing mode: `no`, `main`, or `all`",
+        dest="label_mode",
+        default="main",
+        metavar="<string>",
     )
     parser.add_argument(
         "-s",
@@ -62,6 +94,21 @@ def add_tile_arguments(parser: argparse.ArgumentParser) -> None:
         help="OSM zoom level",
         default=18,
     )
+    parser.add_argument(
+        "--level",
+        default="overground",
+        help="display only this floor level",
+    )
+
+
+def add_tile_arguments(parser: argparse.ArgumentParser) -> None:
+    """Add arguments for tile command."""
+    parser.add_argument(
+        "-c",
+        "--coordinates",
+        metavar="<latitude>,<longitude>",
+        help="coordinates of any location inside the tile",
+    )
     parser.add_argument(
         "-t",
         "--tile",
@@ -126,47 +173,17 @@ def add_render_arguments(parser: argparse.ArgumentParser) -> None:
         help="geo boundary box; if first value is negative, enclose the value "
         "with quotes and use space before `-`",
     )
-    parser.add_argument(
-        "-s",
-        "--scale",
-        metavar="<float>",
-        help="OSM zoom level (may not be integer)",
-        default=18,
-        type=float,
-    )
     parser.add_argument(
         "--cache",
         help="path for temporary OSM files",
         default="cache",
         metavar="<path>",
     )
-    parser.add_argument(
-        "--labels",
-        help="label drawing mode: `no`, `main`, or `all`",
-        dest="label_mode",
-        default="main",
-    )
-    parser.add_argument(
-        "--overlap",
-        dest="overlap",
-        default=12,
-        type=int,
-        help="how many pixels should be left around icons and text",
-    )
-    parser.add_argument(
-        "--mode",
-        default="normal",
-        help="map drawing mode",
-    )
     parser.add_argument(
         "--seed",
         default="",
         help="seed for random",
-    )
-    parser.add_argument(
-        "--level",
-        default=None,
-        help="display only this floor level",
+        metavar="<string>",
     )
 
 
@@ -219,91 +236,3 @@ def progress_bar(
             f"{int(length - fill_length - 1) * ' '}▏{text}"
         )
         sys.stdout.write("\033[F")
-
-
-@dataclass
-class BoundaryBox:
-    """
-    Rectangle that limit space on the map.
-    """
-
-    left: float
-    bottom: float
-    right: float
-    top: float
-
-    @classmethod
-    def from_text(cls, boundary_box: str):
-        """
-        Parse boundary box string representation.
-
-        Note, that:
-            left < right
-            bottom < top
-
-        :param boundary_box: boundary box string representation in the form of
-            <longitude 1>,<latitude 1>,<longitude 2>,<latitude 2> or simply
-            <left>,<bottom>,<right>,<top>.
-        """
-        boundary_box = boundary_box.replace(" ", "")
-
-        matcher = re.match(
-            "(?P<left>[0-9.-]*),(?P<bottom>[0-9.-]*),"
-            + "(?P<right>[0-9.-]*),(?P<top>[0-9.-]*)",
-            boundary_box,
-        )
-
-        if not matcher:
-            logging.fatal("Invalid boundary box.")
-            return None
-
-        try:
-            left: float = float(matcher.group("left"))
-            bottom: float = float(matcher.group("bottom"))
-            right: float = float(matcher.group("right"))
-            top: float = float(matcher.group("top"))
-        except ValueError:
-            logging.fatal("Invalid boundary box.")
-            return None
-
-        if left >= right:
-            logging.fatal("Negative horizontal boundary.")
-            return None
-        if bottom >= top:
-            logging.error("Negative vertical boundary.")
-            return None
-        if (
-            right - left > LONGITUDE_MAX_DIFFERENCE
-            or top - bottom > LATITUDE_MAX_DIFFERENCE
-        ):
-            logging.error("Boundary box is too big.")
-            return None
-
-        return cls(left, bottom, right, top)
-
-    def get_left_top(self) -> (np.array, np.array):
-        """Get left top corner of the boundary box."""
-        return self.top, self.left
-
-    def get_right_bottom(self) -> (np.array, np.array):
-        """Get right bottom corner of the boundary box."""
-        return self.bottom, self.right
-
-    def round(self) -> "BoundaryBox":
-        """Round boundary box."""
-        self.left = round(self.left * 1000) / 1000 - 0.001
-        self.bottom = round(self.bottom * 1000) / 1000 - 0.001
-        self.right = round(self.right * 1000) / 1000 + 0.001
-        self.top = round(self.top * 1000) / 1000 + 0.001
-
-        return self
-
-    def get_format(self) -> str:
-        """
-        Get text representation of the boundary box:
-        <longitude 1>,<latitude 1>,<longitude 2>,<latitude 2>.  Coordinates are
-        rounded to three digits after comma.
-        """
-        return (
-            f"{self.left:.3f},{self.bottom:.3f},{self.right:.3f},{self.top:.3f}"
-        )
diff --git a/roentgen/vector.py b/roentgen/vector.py
index d7e5926..08a3db8 100644
--- a/roentgen/vector.py
+++ b/roentgen/vector.py
@@ -24,9 +24,7 @@ def compute_angle(vector: np.array):
 
 
 def turn_by_angle(vector: np.array, angle: float):
-    """
-    Turn vector by an angle.
-    """
+    """Turn vector by an angle."""
     return np.array(
         (
             vector[0] * np.cos(angle) - vector[1] * np.sin(angle),
@@ -36,16 +34,12 @@ def turn_by_angle(vector: np.array, angle: float):
 
 
 def norm(vector: np.array) -> np.array:
-    """
-    Compute vector with the same direction and length 1.
-    """
+    """Compute vector with the same direction and length 1."""
     return vector / np.linalg.norm(vector)
 
 
 class Line:
-    """
-    Infinity line: Ax + By + C = 0.
-    """
+    """Infinity line: Ax + By + C = 0."""
 
     def __init__(self, start: np.array, end: np.array) -> None:
         # if start.near(end):
@@ -63,15 +57,11 @@ class Line:
         self.c -= self.a * shift.x + self.b * shift.y
 
     def is_parallel(self, other: "Line") -> bool:
-        """
-        If lines are parallel or equal.
-        """
+        """If lines are parallel or equal."""
         return np.allclose(other.a * self.b - self.a * other.b, 0)
 
     def get_intersection_point(self, other: "Line") -> np.array:
-        """
-        Get point of intersection current line with other.
-        """
+        """Get point of intersection current line with other."""
         if other.a * self.b - self.a * other.b == 0:
             return np.array((0, 0))
 
diff --git a/scheme/default.yml b/scheme/default.yml
index 156ae1f..198aaef 100644
--- a/scheme/default.yml
+++ b/scheme/default.yml
@@ -689,25 +689,79 @@ node_icons:
     - tags: {man_made: mast, tower:construction: lattice_guyed}
       shapes: [lattice_guyed]
     - tags: {man_made: mast, tower:type: lighting}
-      shapes: [tube, {shape: light_left, offset: [-3, -3]}, {shape: light_right, offset: [3, -3]}]
+      shapes:
+      - tube
+      - {shape: light_left, offset: [-3, -3]}
+      - {shape: light_right, offset: [3, -3]}
     - tags: {man_made: mast, tower:type: communication}
-      shapes: [tube, {shape: wave_left, offset: [-3, -3]}, {shape: wave_right, offset: [3, -3]}]
-    - tags: {man_made: mast, tower:type: lighting, tower:construction: guyed_tube}
-      shapes: [tube_guyed, {shape: light_left, offset: [-3, -3]}, {shape: light_right, offset: [3, -3]}]
-    - tags: {man_made: mast, tower:type: communication, tower:construction: guyed_tube}
-      shapes: [tube_guyed, {shape: wave_left, offset: [-3, -3]}, {shape: wave_right, offset: [3, -3]}]
-    - tags: {man_made: mast, tower:type: lighting, tower:construction: freestanding}
-      shapes: [tube, {shape: light_left, offset: [-3, -3]}, {shape: light_right, offset: [3, -3]}]
-    - tags: {man_made: mast, tower:type: communication, tower:construction: freestanding}
-      shapes: [tube, {shape: wave_left, offset: [-3, -3]}, {shape: wave_right, offset: [3, -3]}]
-    - tags: {man_made: mast, tower:type: lighting, tower:construction: guyed_lattice}
-      shapes: [lattice_guyed, {shape: light_left, offset: [-4, -3]}, {shape: light_right, offset: [3, -3]}]
-    - tags: {man_made: mast, tower:type: communication, tower:construction: guyed_lattice}
-      shapes: [lattice_guyed, {shape: wave_left, offset: [-4, -3]}, {shape: wave_right, offset: [3, -3]}]
-    - tags: {man_made: mast, tower:type: lighting, tower:construction: lattice}
-      shapes: [lattice, {shape: light_left, offset: [-4, -3]}, {shape: light_right, offset: [3, -3]}]
-    - tags: {man_made: mast, tower:type: communication, tower:construction: lattice}
-      shapes: [lattice, {shape: wave_left, offset: [-4, -3]}, {shape: wave_right, offset: [3, -3]}]
+      shapes:
+      - tube
+      - {shape: wave_left, offset: [-3, -3]}
+      - {shape: wave_right, offset: [3, -3]}
+    - tags:
+        man_made: mast
+        tower:type: lighting
+        tower:construction: guyed_tube
+      shapes:
+      - tube_guyed
+      - {shape: light_left, offset: [-3, -3]}
+      - {shape: light_right, offset: [3, -3]}
+    - tags:
+        man_made: mast
+        tower:type: communication
+        tower:construction: guyed_tube
+      shapes:
+      - tube_guyed
+      - {shape: wave_left, offset: [-3, -3]}
+      - {shape: wave_right, offset: [3, -3]}
+    - tags:
+        man_made: mast
+        tower:type: lighting
+        tower:construction: freestanding
+      shapes:
+      - tube
+      - {shape: light_left, offset: [-3, -3]}
+      - {shape: light_right, offset: [3, -3]}
+    - tags:
+        man_made: mast
+        tower:type: communication
+        tower:construction: freestanding
+      shapes:
+      - tube
+      - {shape: wave_left, offset: [-3, -3]}
+      - {shape: wave_right, offset: [3, -3]}
+    - tags:
+        man_made: mast
+        tower:type: lighting
+        tower:construction: guyed_lattice
+      shapes:
+      - lattice_guyed
+      - {shape: light_left, offset: [-4, -3]}
+      - {shape: light_right, offset: [3, -3]}
+    - tags:
+        man_made: mast
+        tower:type: communication
+        tower:construction: guyed_lattice
+      shapes:
+      - lattice_guyed
+      - {shape: wave_left, offset: [-4, -3]}
+      - {shape: wave_right, offset: [3, -3]}
+    - tags:
+        man_made: mast
+        tower:type: lighting
+        tower:construction: lattice
+      shapes:
+      - lattice
+      - {shape: light_left, offset: [-4, -3]}
+      - {shape: light_right, offset: [3, -3]}
+    - tags:
+        man_made: mast
+        tower:type: communication
+        tower:construction: lattice
+      shapes:
+      - lattice
+      - {shape: wave_left, offset: [-4, -3]}
+      - {shape: wave_right, offset: [3, -3]}
 
     - tags: {man_made: tower, tower:construction: guyed_tube}
       shapes: [tube_guyed]
@@ -718,25 +772,79 @@ node_icons:
     - tags: {man_made: tower, tower:construction: lattice_guyed}
       shapes: [lattice_guyed]
     - tags: {man_made: tower, tower:type: lighting}
-      shapes: [tube, {shape: light_left, offset: [-3, -3]}, {shape: light_right, offset: [3, -3]}]
+      shapes:
+      - tube
+      - {shape: light_left, offset: [-3, -3]}
+      - {shape: light_right, offset: [3, -3]}
     - tags: {man_made: tower, tower:type: communication}
-      shapes: [tube, {shape: wave_left, offset: [-3, -3]}, {shape: wave_right, offset: [3, -3]}]
-    - tags: {man_made: tower, tower:type: lighting, tower:construction: guyed_tube}
-      shapes: [tube_guyed, {shape: light_left, offset: [-3, -3]}, {shape: light_right, offset: [3, -3]}]
-    - tags: {man_made: tower, tower:type: communication, tower:construction: guyed_tube}
-      shapes: [tube_guyed, {shape: wave_left, offset: [-3, -3]}, {shape: wave_right, offset: [3, -3]}]
-    - tags: {man_made: tower, tower:type: lighting, tower:construction: freestanding}
-      shapes: [tube, {shape: light_left, offset: [-3, -3]}, {shape: light_right, offset: [3, -3]}]
-    - tags: {man_made: tower, tower:type: communication, tower:construction: freestanding}
-      shapes: [tube, {shape: wave_left, offset: [-3, -3]}, {shape: wave_right, offset: [3, -3]}]
-    - tags: {man_made: tower, tower:type: lighting, tower:construction: guyed_lattice}
-      shapes: [lattice_guyed, {shape: light_left, offset: [-4, -3]}, {shape: light_right, offset: [3, -3]}]
-    - tags: {man_made: tower, tower:type: communication, tower:construction: guyed_lattice}
-      shapes: [lattice_guyed, {shape: wave_left, offset: [-4, -3]}, {shape: wave_right, offset: [3, -3]}]
-    - tags: {man_made: tower, tower:type: lighting, tower:construction: lattice}
-      shapes: [lattice, {shape: light_left, offset: [-4, -3]}, {shape: light_right, offset: [3, -3]}]
-    - tags: {man_made: tower, tower:type: communication, tower:construction: lattice}
-      shapes: [lattice, {shape: wave_left, offset: [-4, -3]}, {shape: wave_right, offset: [3, -3]}]
+      shapes:
+      - tube
+      - {shape: wave_left, offset: [-3, -3]}
+      - {shape: wave_right, offset: [3, -3]}
+    - tags:
+        man_made: tower
+        tower:type: lighting
+        tower:construction: guyed_tube
+      shapes:
+      - tube_guyed
+      - {shape: light_left, offset: [-3, -3]}
+      - {shape: light_right, offset: [3, -3]}
+    - tags:
+        man_made: tower
+        tower:type: communication
+        tower:construction: guyed_tube
+      shapes:
+      - tube_guyed
+      - {shape: wave_left, offset: [-3, -3]}
+      - {shape: wave_right, offset: [3, -3]}
+    - tags:
+        man_made: tower
+        tower:type: lighting
+        tower:construction: freestanding
+      shapes:
+      - tube
+      - {shape: light_left, offset: [-3, -3]}
+      - {shape: light_right, offset: [3, -3]}
+    - tags:
+        man_made: tower
+        tower:type: communication
+        tower:construction: freestanding
+      shapes:
+      - tube
+      - {shape: wave_left, offset: [-3, -3]}
+      - {shape: wave_right, offset: [3, -3]}
+    - tags:
+        man_made: tower
+        tower:type: lighting
+        tower:construction: guyed_lattice
+      shapes:
+      - lattice_guyed
+      - {shape: light_left, offset: [-4, -3]}
+      - {shape: light_right, offset: [3, -3]}
+    - tags:
+        man_made: tower
+        tower:type: communication
+        tower:construction: guyed_lattice
+      shapes:
+      - lattice_guyed
+      - {shape: wave_left, offset: [-4, -3]}
+      - {shape: wave_right, offset: [3, -3]}
+    - tags:
+        man_made: tower
+        tower:type: lighting
+        tower:construction: lattice
+      shapes:
+      - lattice
+      - {shape: light_left, offset: [-4, -3]}
+      - {shape: light_right, offset: [3, -3]}
+    - tags:
+        man_made: tower
+        tower:type: communication
+        tower:construction: lattice
+      shapes:
+      - lattice
+      - {shape: wave_left, offset: [-4, -3]}
+      - {shape: wave_right, offset: [3, -3]}
 
     - tags: {communication:mobile_phone: "yes"}
       add_shapes: [phone]
@@ -873,7 +981,9 @@ node_icons:
   - group: "Entrances"
     tags:
     - tags: {amenity: parking_entrance}
-      shapes: [{shape: p, offset: [-1, 0]}, {shape: arrow_right, offset: [4, 5]}]
+      shapes:
+      - {shape: p, offset: [-1, 0]}
+      - {shape: arrow_right, offset: [4, 5]}
     - tags: {amenity: parking_entrance, parking: underground}
       shapes: [{shape: p, offset: [-1, 0]}, {shape: arrow_down, offset: [4, 5]}]
     - tags: {amenity: parking_entrance, parking: multi-storey}
diff --git a/test/test_boundary_box.py b/test/test_boundary_box.py
index 8f229e3..3adfd6c 100644
--- a/test/test_boundary_box.py
+++ b/test/test_boundary_box.py
@@ -1,13 +1,14 @@
 """
 Test boundary box.
 """
-from roentgen.ui import BoundaryBox
+from roentgen.boundary_box import BoundaryBox
 
 __author__ = "Sergey Vartanov"
 __email__ = "me@enzet.ru"
 
 
 def test_round_zero_coordinates() -> None:
+    """Test rounding for zero coordinates."""
     assert (
         BoundaryBox(0, 0, 0, 0).round().get_format()
         == "-0.001,-0.001,0.001,0.001"
@@ -15,6 +16,7 @@ def test_round_zero_coordinates() -> None:
 
 
 def test_round_coordinates() -> None:
+    """Test rounding coordinates."""
     box: BoundaryBox = BoundaryBox(
         10.067596435546875,
         46.094186149226466,