add liskov demo

src/doodles/examples/liskov.py

@@ -0,0 +1,25 @@
+"""
+Demo of the interchangable nature of these classes.
+"""
+from doodles import Polygon, Line, Rectangle, Circle, Color
+import random
+import math
+
+types = [Polygon, Line, Rectangle, Circle]
+
+
+def rainbow(t) -> tuple[int, int, int]:
+    """cycles through colors based on time"""
+    t = t % 1.0
+
+    r = int(255 * (1 + math.sin(2 * math.pi * (t + 0.0 / 3))) / 2)
+    g = int(255 * (1 + math.sin(2 * math.pi * (t + 1.0 / 3))) / 2)
+    b = int(255 * (1 + math.sin(2 * math.pi * (t + 2.0 / 3))) / 2)
+
+    return (r, g, b)
+
+
+def create():
+    for _ in range(100):
+        DoodleType = random.choice(types)
+        doodle = DoodleType().random().animate("color", rainbow)

src/doodles/shapes.py

@@ -126,7 +126,7 @@ class Polygon(Doodle):
             self._points.append(point)
         return self
 
-    def random(self, n_points: int) -> Self:
+    def random(self, n_points: int = 5) -> Self:
         super().random()
         for _ in range(n_points):
             self.point((random.random() * 100 - 50, random.random() * 100 - 50))