SICP ex 2.45
(define (split b1 b2) (lambda (painter n) (if (= n 0) painter (let ((smaller ((split b1 b2) painter (- n 1)))) (b1 painter (b2 smaller smaller))))))
(define (split b1 b2) (lambda (painter n) (if (= n 0) painter (let ((smaller ((split b1 b2) painter (- n 1)))) (b1 painter (b2 smaller smaller))))))