;;; Scheme Recursive Art Contest Entry
;;;
;;; Please do not include your name or personal info in this file.
;;;
;;; Title: Circles... or Triangle?
;;;
;;; Description:
;;;    The never-ending battle between
;;;    circles and triangles will always
;;;    cause a recursive confusion.

(define c (list "#0000ff" "#ff0000" "#00ff00" "#ffff00" "#ff8000" "#9933ff"))
(define (move x y) (begin (penup) (setposition x y) (pendown)))

(define (f i x y r co)
  (if (> i 0)
    (if (null? co)
      (begin (move x y) (color (car c)) (circle r) (f (- i 1) (- x 2) (+ y (+ r r) -2) (- r 2) (cdr c)) (f (- i 1) (+ x (- (* r (sqrt 2))) -2 (sqrt 2)) (+ y (- (* r (sqrt 2))) (sqrt 2)) (- r 2) (cdr c)) (f (- i 1) (+ x (* r (sqrt 2)) (- (sqrt 2)) -2) (+ y (- (* r (sqrt 2))) (sqrt 2)) (- r 2) (cdr c)))
      (begin (move x y) (color (car co)) (circle r) (f (- i 1) (- x 2) (+ y (+ r r) -2) (- r 2) (cdr co)) (f (- i 1) (+ x (- (* r (sqrt 2))) -2 (sqrt 2)) (+ y (- (* r (sqrt 2))) (sqrt 2)) (- r 2) (cdr co)) (f (- i 1) (+ x (* r (sqrt 2)) (- (sqrt 2)) -2) (+ y (- (* r (sqrt 2))) (sqrt 2)) (- r 2) (cdr co)))
    )
    (if (null? co)
      nil
      nil
    )
  )
)

(define (draw)
  (bgcolor "#000000")
  (showturtle)
  (speed 90000)
  (f 7 10 0 22 c)
  (hideturtle)
  (exitonclick))

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