問題2.52
(add-load-path ".") (load "2.49.scm") (define (corner-split2 painter n) (if (= n 0) painter (let ((right (right-split painter (- n 1))) ((up (rotate90 (right-split (rotate270 painter)))))) (let ((top-left (beside up up)) (bottom-right (below right right)) (corner (corner-split painter (- n 1)))) (beside (below painter top-left) (below bottom-right corner))))))