sicp exercise 2.50

;; Exercise 2.50.  Define the transformation flip-horiz, which flips painters horizontally, and transformations that rotate painters counterclockwise by 180 degrees and 270 degrees.


(define (flip-horiz painter)
  (transform-painter painter
                     (make-vect 0.0 1.0)   ;; new origin
                     (make-vect 0.0 0.0)   ;; new edge1
                     (make-vect 1.0 1.0))) ;; new edge2
                    
(define (rotate-180-deg-counterclockwise painter)
  (transform-painter painter
                     (make-vect 1.0 1.0)   ;; new origin
                     (make-vect 0.0 1.0)   ;; new edge1
                     (make-vect 1.0 0.0))) ;; new edge2


(define (rotate-270-deg-counterclockwise painter)
  (transform-painter painter
                     (make-vect 0.0 1.0)   ;; new origin
                     (make-vect 0.0 0.0)   ;; new edge1
                     (make-vect 1.0 1.0))) ;; new edge2