2-51.scm

;生成 p1 在下 p2 在上的图
(define (beside painter1 painter2)
  (let ((split-point (make-vect 0.0 0.5)))
    (let ((paint-left  (transform-painter 
                        painter1
                        (make-vect 0.0 0.0)
                        (make-vect 1.0 0.0)
                        split-point))
          (paint-right (transform-painter
                        painter2
                        split-point
                        (make-vect 1.0 0.5)
                        (make-vect 0.0 1.0))))
      (lambda (frame)
        (paint-left frame)
        (paint-right frame)))))

(define (beside painter1 painter2)
  (rotate90 (beside (rotate270 painter1)) (rotate270 painter2)))