Implement till 2.53

ex-2_44-52.scm

@@ -258,12 +258,64 @@
 (display "\nex-2.51\n")
 
 ; First implementation is at the beginning of this file.
-(draw-to-py ((corner-split painter-wave 4) simple-frame) "corner-split-4")
-(draw-to-py ((below painter-x painter-diamond) simple-frame) "x-below-diamond")
+(draw-to-py ((below painter-x painter-diamond) simple-frame) "x-below-diamond-1")
 
+(define (below painter1 painter2)
+  (rotate270 (beside (rotate90 painter2) (rotate90 painter1))))
 
+(draw-to-py ((below painter-x painter-diamond) simple-frame) "x-below-diamond-2")
 
 
 (display "\nex-2.52\n")
 
 
+; a.
+(define painter-wave-smile
+  (segments->painter
+    (list (make-line 0.4 0 0.5 0.33)
+          (make-line 0.5 0.33 0.6 0.0)
+          (make-line 0.25 0.0 0.33 0.5)
+          (make-line 0.33 0.5 0.3 0.6)
+          (make-line 0.3 0.6 0.1 0.4)
+          (make-line 0.1 0.4 0.0 0.6)
+          (make-line 0.0 0.6 0.0 0.8)
+          (make-line 0.0 0.8 0.1 0.6)
+          (make-line 0.1 0.6 0.33 0.65)
+          (make-line 0.33 0.65 0.4 0.65)
+          (make-line 0.4 0.65 0.35 0.8)
+          (make-line 0.43 0.87 0.46 0.87) ; left eye
+          (make-line 0.54 0.87 0.57 0.87) ; right eye
+          (make-line 0.45 0.75 0.55 0.75) ; smile
+          (make-line 0.35 0.8 0.4 1.0)
+          (make-line 0.4 1.0 0.6 1.0)
+          (make-line 0.75 0.0 0.6 0.45)
+          (make-line 0.6 0.45 1.0 0.15)
+          (make-line 1.0 0.15 1.0 0.35)
+          (make-line 1.0 0.35 0.8 0.65)
+          (make-line 0.8 0.65 0.6 0.65)
+          (make-line 0.6 0.65 0.65 0.8)
+          (make-line 0.65 0.8 0.6 1.0))))
+
+(draw-to-py (painter-wave-smile simple-frame) "wave-smile")
+
+; b.
+(define (corner-split-adapted painter n)
+  (if (= n 0)
+      painter
+      (let ((up (up-split painter (- n 1)))
+            (right (right-split painter (- n 1))))
+        (let ((top-left up)
+              (bottom-right right)
+              (corner (corner-split-adapted painter (- n 1))))
+          (beside (below painter top-left)
+                  (below bottom-right corner))))))
+
+(draw-to-py ((corner-split-adapted painter-wave 3) simple-frame) "corner-split-3")
+
+; c. didn't do anything here
+(define (square-of-four tl tr bl br)
+  (lambda (painter)
+    (let ((top (beside (tl painter) (tr painter)))
+          (bottom (beside (bl painter) (br painter))))
+      (below bottom top))))
+