;;; Your entry for the Scheme contest
;;;
;;; Title:
;;;  Helix Rings
;;;
;;; Description:
;;;  Not quite concentric?
;;;  Tail-end recursion on arcs
;;;  Form nested braid loops

(define colors (list 'navy 'gray12 'gold 'navy))

(define (pickcolor n x)
  (if (= (modulo n 4) 0)
      (car x)
      (pickcolor (- n 1) (cdr x))))

(define n 0)
(define (arc x y z a)
  (color (pickcolor n colors))
  (set! n (+ n 1))
  (if (> y 0)
  (begin (circle x z)
  (circle (- x) a)
  (arc x (- y 1) z a)) 0))

(define (drawcircles xc yc r n)
  (if (= n 0) 0 (begin 
  (pu)
  (goto xc yc)
  (seth 0)
  (pd)
  (arc r 36 165 115)
  (drawcircles (/ xc 2) (/ yc 2) (/ r 2) (- n 1)))))

;(drawcircles 80 200 50 7)
(speed 0)
(drawcircles 130 200 50 7)

;squiggle
(pu)
(goto -250 -250)
(seth 60)
(color 'red)
(pd)
(circle -15 60)
(circle 15 60)


(ht)
;(exitonclick)

;wordcount 124