;;;;;;;;;;;;;;;;;;
;;; ps4-ans.ss ;;;
;;;;;;;;;;;;;;;;;;

;;; Henderson picture language adapted to DrScheme
;;; Uses MzScheme module system for some loading and renaming
;;; 
;;; Use language "Textual (MzScheme, includes R5RS)" in DrScheme

(require "primitives.ss")
(require (lib "include.ss"))
(include "mit-macros.scm")
(include "mit-support.scm")
(include "hutils.scm")
(include "prmpnt.scm")
(include "hend.scm")

;;; recursive complex means of combination (from book)

(define (right-split painter n)
  (if (= n 0)
      painter
      (let ((smaller (right-split painter (- n 1))))
        (beside painter (below smaller smaller)))))

;;; up-split left as an exercise...
(define (up-split painter n)
  (error "up-split left as exercise"))

(define (corner-split painter n)
  (if (= n 0)
      painter
      (let ((up (up-split painter (- n 1)))
            (right (right-split painter (- n 1))))
        (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))))))

(define (square-limit painter n)
  (let ((quarter (corner-split painter n)))
    (let ((half (beside (flip-horiz quarter) quarter)))
      (below (flip-vert half) half))))

;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Your answers here  ;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;