demo that you can animate any property

src/doodles/examples/clock.py

@@ -1,17 +1,26 @@
 import time
+import math
 from doodles import Circle, Color, Line, Group
 
 
 def color_func(t):
-    print("updating color")
     cycle = [Color.RED, Color.ORANGE, Color.GREEN, Color.BLUE]
     return cycle[int(t) % 4]
 
 
+def size_func_factory(min_size, factor):
+    def size_function(t):
+        return math.sin(t) * factor + min_size
+
+    return size_function
+
+
 def create():
     g = Group().pos(400, 300)
-    Circle(g).radius(300).color(Color.BLACK).z(1)
-    Circle(g).radius(290).color(Color.BROWN).z(10)
+    Circle(g).color(Color.BLACK).z(1).animate("radius", size_func_factory(260, 50))
+    Circle(g).z(10).animate("color", color_func).animate(
+        "radius", size_func_factory(250, 50)
+    )
     Circle(g).radius(20).color(Color.BLACK).z(50)
     # Line(g).vec(
     #     lambda: time.time() % 60 / 60 * 360,
@@ -19,4 +28,4 @@ def create():
     # ).z(100)
 
     l = Line(g).vec(0, 200).z(100).animate("degrees", lambda t: t % 60 / 60 * 360)
-    l.animate("color", color_func)
+    # l.animate("color", color_func)

src/doodles/lines.py

@@ -81,7 +81,7 @@ class Line(Doodle):
         """
         Alternate setter, like calling vec(new_degrees, old_magnitude).
         """
-        magnitude = math.sqrt(self._offset_vec[0]**2 + self._offset_vec[1]**2)
+        magnitude = math.sqrt(self._offset_vec[0] ** 2 + self._offset_vec[1] ** 2)
         return self.to(
             magnitude * math.cos(math.radians(degrees)),
             magnitude * math.sin(math.radians(degrees)),