Add some sample cows.

src/Cdl/SampleCows.hs

@@ -0,0 +1,11 @@
+module Cdl.SampleCows where
+import Cdl.Cow
+
+regularPolygonCow :: Int -> CowBehavior ()
+regularPolygonCow n = repeatTimes n $ move 10 >> return (360 `div` n)
+
+squareCow :: CowBehavior ()
+squareCow = repeatTimes 4 $ move 10 >> turn 90
+
+pacingCow :: CowBehavior ()
+pacingCow = move 10 >> turn 180 >> move 10