;;; Scheme Recursive Art Contest Entry
;;;
;;; Please do not include your name or personal info in this file.
;;;
;;; Title: <Turtles>
;;;
;;; Description:
;;;   <Turtles within more
;;;    turtles drawn by even more
;;;    turtles all the way down.>

(define (draw)
  (all-the-way-down 0 -1 180)
  (hideturtle)
  (exitonclick))

(define (all-the-way-down count direction y)
    (if (< count 4)
        (begin
            (draw-turtle "medium sea green" direction 100 -75 y)
            (all-the-way-down (+ count 1) (* direction (- 1)) (- y 125)))
    )
)

(define (draw-turtle col direction shell-size x1 y1)
    (if (> shell-size 10)
        (begin 
            (penup)
            (color col)
            (if (equal? direction -1)
                (goto x1 y1)
                (goto (+ x1 (* 2 shell-size) (quotient shell-size 2)) y1)
                )
            (pendown)
            (begin_fill)
            (circle (quotient shell-size 4))
            (penup)
            (goto (+ x1 (* 2 shell-size)) y1)
            (pendown)
            (circle shell-size 180)
            (forward (quotient shell-size 4))
            (circle (quotient shell-size 5) 180)
            (forward (quotient shell-size 4))
            (goto (+ x1 (* 2 shell-size) (- (quotient shell-size 2.5))) y1)
            (left 180)
            (forward (quotient shell-size 4))
            (circle (quotient shell-size 5) 180)
            (forward (quotient shell-size 4))
            (end_fill)
            (penup)
            (define x2 (+ x1 (quotient shell-size 3)))
            (define y2 (+ y1 (quotient shell-size 4)))
            (if (equal? col "medium sea green")
                (define col "white")
                (define col "medium sea green"))
            (draw-turtle col (* (- 1) direction) (quotient shell-size 1.75) x2 y2)
        )
    )
)

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