Data commit

Task/Koch-curve/Racket/koch-curve.rkt

@@ -0,0 +1,27 @@
+#lang racket
+
+(require metapict)
+
+; rot: rotate d degrees around point p, where c is a point or curve
+(def (rot d p c)
+  (rotated-aboutd d p c))
+
+(define (koch a b n)
+  (match n
+    [0 (draw (curve a -- b))]
+    [_ (def 1/3ab (med 1/3 a b))
+       (def 2/3ab (med 2/3 a b))
+       (draw (koch a 1/3ab                      (- n 1))
+             (koch 1/3ab (rot 60 1/3ab 2/3ab)   (- n 1))
+             (koch (rot 60 1/3ab 2/3ab) 2/3ab   (- n 1))
+             (koch 2/3ab b                      (- n 1)))]))
+
+(define (snow n)
+  (def a (pt 0 0))
+  (def b (pt 1 0))
+  (def c (rot 60 a b))
+  (draw (koch b a n)
+        (koch c b n)
+        (koch a c n)))
+
+(scale 4 (snow 2))