Initial data commit

Task/Pythagoras-tree/Racket/pythagoras-tree.rkt

@@ -0,0 +1,31 @@
+#lang racket
+(require racket/draw pict)
+
+(define (draw-pythagoras-tree order x0 y0 x1 y1)
+  (λ (the-dc dx dy)
+    (define (inr order x0 y0 x1 y1)
+      (when (positive? order)
+        (let* ((y0-1 (- y0 y1))
+               (x1-0 (- x1 x0))
+               (x2 (+ x1 y0-1))
+               (y2 (+ y1 x1-0))
+               (x3 (+ x0 y0-1))
+               (y3 (+ y0 x1-0))
+               (x4 (+ x2 x3 (/ (+ x0 x2) -2)))
+               (y4 (+ y2 y3 (/ (+ y0 y2) -2)))
+               (path (new dc-path%)))
+          (send* path [move-to x0 y0]
+            [line-to x1 y1] [line-to x2 y2] [line-to x3 y3]
+            [close])
+          (send the-dc draw-path path dx dy)
+          (inr (sub1 order) x3 y3 x4 y4)
+          (inr (sub1 order) x4 y4 x2 y2))))
+
+    (define old-brush (send the-dc get-brush))
+    (define old-pen (send the-dc get-pen))
+    (send the-dc set-pen (new pen% [width 1] [color "black"]))
+    (inr (add1 order) x0 y0 x1 y1)
+    (send the-dc set-brush old-brush)
+    (send the-dc set-pen old-pen)))
+
+(dc (draw-pythagoras-tree 7 (+ 200 32) 255 (- 200 32) 255) 400 256)