1 files changed, 99 insertions, 11 deletions
diff --git a/coding-exercises/2/49.rkt b/coding-exercises/2/49.rkt
index 688364a..9ee7fe9 100644
--- a/coding-exercises/2/49.rkt
+++ b/coding-exercises/2/49.rkt
@@ -1,21 +1,109 @@
 #lang racket
-(require (only-in sicp-pict 
-                  paint 
-                  segments->painter))
 (require "../../shared/pict.rkt")
+(require "../../shared/lists.rkt")
 
 (define (outline frame)
-  (display frame)
-  (let ((corner 
-          (add-vect 
+  (let ((corner
+          (add-vect
             (edge1-frame frame)
             (edge2-frame frame)))
         (origin (origin-frame frame))
         (e1 (edge1-frame frame))
         (e2 (edge2-frame frame)))
-    (segments->painter 
-      (list (make-segment origin e1)
-            (make-segment e1 corner)
-            (make-segment corner e2)
-            (make-segment e2 origin)))))
+    ((segments->painter
+       (list (make-segment origin e1)
+             (make-segment e1 corner)
+             (make-segment corner e2)
+             (make-segment e2 origin))) frame)))
 (paint outline)
+
+(define (x frame)
+  ((segments->painter
+     (list (make-segment (origin-frame frame)
+                         (add-vect
+                           (edge1-frame frame)
+                           (edge2-frame frame)))
+           (make-segment (edge1-frame frame)
+                         (edge2-frame frame))))
+   frame))
+(paint x)
+
+(define (midpoint-segment s)
+  (let ((start (start-segment s))
+        (end (end-segment s)))
+    (let ((midpoint
+            (make-vect
+              (/ (+ (xcor-vect end) (xcor-vect start)) 2)
+              (/ (+ (ycor-vect end) (ycor-vect start)) 2))))
+      midpoint)))
+
+(define (enumerate-corners frame)
+  (list
+    (origin-frame frame)
+    (edge1-frame frame)
+    (add-vect
+      (edge1-frame frame)
+      (edge2-frame frame))
+    (edge2-frame frame)))
+
+(define (close-line line-points)
+  (append line-points (list (car line-points))))
+
+(define (enumerate-segments frame)
+  (map
+    (lambda (pair)
+      (make-segment (car pair) (cadr pair)))
+    (enumerate-windows
+      (close-line (enumerate-corners frame))
+      2)))
+
+(define (line-points->segments points)
+  (map
+   (lambda (pair)
+     (make-segment (car pair) (cadr pair)))
+   (enumerate-windows
+     points
+     2)))
+
+(define (diamond frame)
+  ((segments->painter
+     (line-points->segments
+       (close-line
+         (map
+           midpoint-segment
+           (enumerate-segments frame)))))
+   frame))
+(paint diamond)
+
+(define (wave frame)
+  (let ((wave-points
+          (list
+            (make-vect 0.24 0)
+            (make-vect 0.37 0.5)
+            (make-vect 0.3 0.6)
+            (make-vect 0.15 0.5)
+            (make-vect 0 0.7)
+            (make-vect 0 0.85)
+            (make-vect 0.15 0.65)
+            (make-vect 0.35 0.7)
+            (make-vect 0.4 0.7)
+            (make-vect 0.3 0.85)
+            (make-vect 0.36 1)
+            (make-vect 0.57 1)
+            (make-vect 0.62 0.855)
+            (make-vect 0.55 0.7)
+            (make-vect 0.65 0.7)
+            (make-vect 1 0.35)
+            (make-vect 1 0.25)
+            (make-vect 0.55 0.52)
+            (make-vect 0.7 0)
+            (make-vect 0.55 0)
+            (make-vect 0.45 0.4)
+            (make-vect 0.34 0))))
+    ((segments->painter
+               (append
+                 (enumerate-segments frame)
+                 (line-points->segments
+                  (close-line
+                    wave-points)))) frame)))
+(paint wave)