diff --git a/README.md b/README.md
index 4893089..a8247a2 100644
--- a/README.md
+++ b/README.md
@@ -75,8 +75,9 @@ python -m turtle_challenges dashed-line
 | --- | --- | --- |
 | 1. Draw a square | `turtle-challenges square` | `draw_square` |
 | 2. Draw a dashed line | `turtle-challenges dashed-line` | `draw_dashed_line` |
+| 3. Draw different shapes | `turtle-challenges shapes` | `draw_shape`, `draw_shapes`, `random_color` |
 
-Challenges 3 to 5 are added by milestones 003 and 004.
+Challenges 4 and 5 are added by milestone 004.
 
 `turtle-challenges --help` lists the challenges. If the command prints that the turtle module needs Tk, install Tk as described under Requirements.
 
@@ -132,8 +133,10 @@ Open `build/html/index.html` in a browser. Any Doxygen warning fails the build,
 │   ├── constants.py           every constant of the project
 │   ├── pen.py                 the Pen and Window protocols the challenges use
 │   ├── window.py              opens the turtle window and creates the turtle
+│   ├── colors.py              random_color and random_palette_color
 │   ├── square.py              challenge 1: draw_square
 │   ├── dashed_line.py         challenge 2: draw_dashed_line
+│   ├── shapes.py              challenge 3: draw_shape, draw_shapes
 │   └── cli.py                 the turtle-challenges command
 ├── tests/                     pytest tests and the recording fake pen
 ├── Doxyfile                   Doxygen configuration
diff --git a/src/turtle_challenges/cli.py b/src/turtle_challenges/cli.py
index 69bbc1e..2173106 100644
--- a/src/turtle_challenges/cli.py
+++ b/src/turtle_challenges/cli.py
@@ -10,10 +10,12 @@ from functools import partial
 from turtle_challenges.constants import (
     CHALLENGE_DASHED_LINE,
     CHALLENGE_NAMES,
+    CHALLENGE_SHAPES,
     CHALLENGE_SQUARE,
 )
 from turtle_challenges.dashed_line import draw_dashed_line
 from turtle_challenges.pen import Pen
+from turtle_challenges.shapes import draw_shapes
 from turtle_challenges.square import draw_square
 from turtle_challenges.window import (
     TurtleUnavailableError,
@@ -52,6 +54,7 @@ def build_challenges(pen: Pen) -> dict[str, Callable[[], None]]:
     return {
         CHALLENGE_SQUARE: partial(draw_square, pen),
         CHALLENGE_DASHED_LINE: partial(draw_dashed_line, pen),
+        CHALLENGE_SHAPES: partial(draw_shapes, pen),
     }
 
 
diff --git a/src/turtle_challenges/constants.py b/src/turtle_challenges/constants.py
index b756d5b..ba9fd58 100644
--- a/src/turtle_challenges/constants.py
+++ b/src/turtle_challenges/constants.py
@@ -68,8 +68,12 @@ CHALLENGE_SQUARE = "square"
 ## Command line name of challenge 2.
 CHALLENGE_DASHED_LINE = "dashed-line"
 
+## Command line name of challenge 3.
+CHALLENGE_SHAPES = "shapes"
+
 ## Names of the challenges on the command line, in the order of the course.
 CHALLENGE_NAMES: tuple[str, ...] = (
     CHALLENGE_SQUARE,
     CHALLENGE_DASHED_LINE,
+    CHALLENGE_SHAPES,
 )