diff --git a/map_machine/doc/draw_elements.py b/map_machine/doc/draw_elements.py
index 5dbf678..c87ce8f 100644
--- a/map_machine/doc/draw_elements.py
+++ b/map_machine/doc/draw_elements.py
@@ -128,12 +128,14 @@ class Grid:
         return osm_way
 
     def add_relation(self, tags: Tags, members: list[OSMMember]) -> OSMRelation:
+        """Connect objects on the gird with relations."""
         osm_relation: OSMRelation = OSMRelation(tags, self.relation_id, members)
         self.osm_data.add_relation(osm_relation)
         self.relation_id += 1
         return osm_relation
 
     def add_text(self, text: str, i: int, j: int) -> None:
+        """Add simple text label to the grid."""
         self.texts.append((text, i, j))
 
     def get_boundary_box(self) -> BoundaryBox:
@@ -178,7 +180,9 @@ class Grid:
 
 def draw_overlapped_ways(types: list[dict[str, str]], path: Path) -> None:
     """
-    Draw two sets of ways intersecting each other to show how they overlapping.
+    Draw two sets of ways intersecting each other.
+
+    The goal is to show check priority.
     """
     grid: Grid = Grid(0.00012, 0.00012)
 
diff --git a/map_machine/doc/moire_manager.py b/map_machine/doc/moire_manager.py
index abce951..e24f14e 100644
--- a/map_machine/doc/moire_manager.py
+++ b/map_machine/doc/moire_manager.py
@@ -230,7 +230,7 @@ class MapMachineHTML(MapMachineMoire, DefaultHTML):
 
 class MapMachineOSMWiki(MapMachineMoire, DefaultWiki):
     """
-    OpenStreetMap wiki.
+    Moire convertor to OpenStreetMap wiki markup.
 
     See https://wiki.openstreetmap.org/wiki/Main_Page
     """
@@ -243,7 +243,7 @@ class MapMachineOSMWiki(MapMachineMoire, DefaultWiki):
         )
 
     def osm(self, arg: Arguments) -> str:
-        """OSM tag key or key–value pair of tag."""
+        """Add special OSM tag key or key–value pair of tag."""
         spec: str = self.clear(arg[0])
         if "=" in spec:
             key, tag = spec.split("=")
@@ -252,11 +252,11 @@ class MapMachineOSMWiki(MapMachineMoire, DefaultWiki):
         return f"{{{{Tag|{spec}}}}}"
 
     def color(self, arg: Arguments) -> str:
-        """Simple color sample."""
+        """Add color box on the wiki page with specified color."""
         return f"{{{{Color box|{self.clear(arg[0])}}}}}"
 
     def icon(self, arg: Arguments) -> str:
-        """Image with Röntgen icon."""
+        """Process image with Röntgen icon."""
         size: str = self.clear(arg[1]) if len(arg) > 1 else "16"
         shape_id: str = self.clear(arg[0])
         name: str = self.extractor.get_shape(shape_id).name
@@ -269,15 +269,15 @@ class MapMachineMarkdown(MapMachineMoire, DefaultMarkdown):
     images = {}
 
     def color(self, arg: Arguments) -> str:
-        """Simple color sample."""
+        """Ignore colors in Markdown."""
         return self.clear(arg[0])
 
     def icon(self, arg: Arguments) -> str:
-        """Image with Röntgen icon."""
+        """Process image with Röntgen icon."""
         return f"[{self.clear(arg[0])}]"
 
     def kbd(self, arg: Arguments) -> str:
-        """Keyboard key."""
+        """Process keyboard key."""
         return f"<kbd>{self.clear(arg[0])}</kbd>"
 
     def no_wrap(self, arg: Arguments) -> str:
@@ -285,7 +285,7 @@ class MapMachineMarkdown(MapMachineMoire, DefaultMarkdown):
         return f'<span style="white-space: nowrap;">{self.parse(arg[0])}</span>'
 
     def formal(self, arg: Arguments) -> str:
-        """Formal variable."""
+        """Process formal variable."""
         return f"<{self.parse(arg[0])}>"
 
 
diff --git a/map_machine/feature/direction.py b/map_machine/feature/direction.py
index d3b69f8..3d393a4 100644
--- a/map_machine/feature/direction.py
+++ b/map_machine/feature/direction.py
@@ -21,8 +21,9 @@ DEFAULT_ANGLE: float = np.pi / 30.0
 
 def parse_vector(text: str) -> Optional[np.ndarray]:
     """
-    Parse vector from text representation: compass points or 360-degree
-    notation.  E.g. "NW", "270".
+    Parse vector from text representation.
+
+    Compass points or 360-degree notation.  E.g. "NW", "270".
 
     :param text: vector text representation
     :return: parsed normalized vector
@@ -58,6 +59,8 @@ class Sector:
 
     def __init__(self, text: str, angle: Optional[float] = None) -> None:
         """
+        Construct sector from text representation.
+
         :param text: sector text representation (e.g. "70-210", "N-NW")
         :param angle: angle in degrees
         """
@@ -125,6 +128,8 @@ class DirectionSet:
 
     def __init__(self, text: str) -> None:
         """
+        Construct direction set from text representation.
+
         :param text: direction tag value
         """
         self.sectors: Iterator[Optional[Sector]] = map(Sector, text.split(";"))
diff --git a/map_machine/feature/tree.py b/map_machine/feature/tree.py
index 1a4652a..5b0526f 100644
--- a/map_machine/feature/tree.py
+++ b/map_machine/feature/tree.py
@@ -1,3 +1,9 @@
+"""
+Drawing tree features on the map.
+
+If radius of trunk or crown are specified they are displayed with simple
+circles.
+"""
 import numpy as np
 from colour import Color
 from svgwrite import Drawing