;;; Scheme Recursive Art Contest Entry
;;;
;;; Please do not include your name or personal info in this file.
;;;
;;; Title: Revolution
;;;
;;; Description:
;;;  Is the world spinning?
;;;  Or is it just standing still
;;;  while I spin around?

(define c1 "#00FF00")
(define c2 "#0000FF")

(define (arc x size col1 col2)
	(if (= x 0) nil
	(begin 
	(forward (* 12. size))
	(begin_fill)
	(forward size)
	(right 90)
	(forward size)
	(right 90)
	(forward (* size 2))
	(right 90)
	(forward (* size 2))
	(right 90)
	(forward (* size 2))
	(right 90)
	(forward size)
	(end_fill)
	(right 90)
	(forward size)
	(color c1)
	(begin_fill)
	(circle size)
	(end_fill)
	(color c2)
	(right 180)
	(begin_fill)
	(circle size)
	(end_fill)
	(right 180)
	(forward (* 12. size))
	(right 180)
	(right (/ 360 15))
	(color "#000000")
	(arc (- x 1) size col1 col2)
	)
	)
)

(define (wheel x y size c c1 c2)
	(setposition x y)
	(if (= c 0) nil
		(begin
			(arc 15 size c1 c2)
			(right 12)
			(wheel x y (* size 0.83) (- c 1) c1 c2)
		)
	)
)
(define (draw)
  (speed 0)
  (pu)
  (wheel -130 130 10 20 c1 c2)
  (wheel 130 130 10 20 c2 c1)
  (wheel -130 -130 10 20 c2 c1)
  (wheel 130 -130 10 20 c1 c2)
  (setposition 0 -130)
  (setheading 90)
  (color "#FFFFFF")
  (begin_fill)
  (circle 130)
  (end_fill)
  (color "#000000")
  (wheel 0 0 10 20 c1 c2)
  (hideturtle)
  (exitonclick))

; Please leave this last line alone.  You may add additional procedures above
; this line.
(draw)