SICP_2.52-2.53 

 1 ;;;;;;;;;;;;;;;;;2.52
 2 (define (corner-split painter n)
 3   (if (= n 0)
 4       painter
 5       (let ((up (up-split painter (- n 1)))
 6             (right (right-split painter (- n 1)))
 7             (corner (corner-split painter (- n 1))))
 8         (beside (below painter up)
 9                 (below right corner)))))
10 
11 ;;;;;;;;;;;;;;;;2.53
12 (define (square-limit painter n)
13   (let ((combine (square-of-four identity flip-horiz
14                                  flip-vect rotate180))
15         (combine (corner-split painter n)))))

 

posted @ 2017-02-23 15:20  lan126  阅读(165)  评论(0)  编辑  收藏  举报