;;; Scheme Recursive Art Contest Entry
;;;
;;; Please do not include your name or personal info in this file.
;;;
;;; Title: <Hal 9000 - (Recursion Edition)>
;;;
;;; Description:
;;;   <Please shift the bins, HAL
;;;    Sorry STUDENT, I'm afraid
;;;    I cannot do that.>


(define (draw)

  (define (rgb_255 r g b) (rgb (/ r 255) (/ g 255) (/ b 255)))

  (define (step fv iv steps)
    (/ (- fv iv) steps)
  )

  (define (center_circle rad r g b)
    (setposition rad -120)
    (color (rgb_255 r g b))
    (circle rad)
  )

  (define (ring rad1 rad2 r g b)
    (begin_fill)
    (center_circle rad1 r g b)
    (center_circle rad2 r g b)
    (end_fill)
  )

  (define (ring_gradient radi ri gi bi radf rf gf bf steps)
    (define rad_diff (step radf radi steps))
    (define (draw_ring rad r g b)
      (ring rad (+ rad rad_diff) r g b)

      (if (< rad radf)
          (draw_ring (+ rad rad_diff) (+ r (step rf ri steps)) (+ g (step gf gi steps)) (+ b (step bf bi steps)))
      )
    )

    (draw_ring radi ri gi bi)
  )

  (define (boxes forw angle steps)
    (if (> steps 0) (begin (forward forw) (right angle) (boxes (+ forw 1.5) angle (- steps 1))))
  )

  (define (spiral h ri gi bi rf gf bf steps)
    (define factor (/ steps 8))
    (setheading h)
    (setposition -50 -50)
    (define (squares r g b n stepsleft)
      (if (> stepsleft 0)
        (begin (color (rgb_255 r g b))
        (boxes n 89.65 9)
        (squares (+ r (step rf ri factor)) (+ g (step gf gi factor)) (+ b (step bf bi factor)) (+ n 12) (- stepsleft 1)))
      )

    )

    (squares ri gi bi 125 factor)
    (penup)
    (setposition 0 0)
    (setheading 0)
  )

  (define (forward_angle f a) (forward f) (right a))

  (bgcolor "black")



  (spiral 0 0 0 0 150 0 0 850)
  (hideturtle)
  (setposition -100 -250)
  (color (rgb_255 60 60 60))
  (begin_fill)
  (forward_angle 500 90)
  (forward_angle 200 90)
  (forward_angle 500 90)
  (forward_angle 200 90)
  (end_fill)

  (setposition 0 -120)





  (ring_gradient 0 255 255 255 10 253 255 40 30)
  (ring_gradient 10 244 24 29 80 0 0 0 24)
  (ring_gradient 80 76 76 76 86 115 115 115 5)


  (exitonclick))

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