(define (circle n radius s)
    (define (loop i angle)
        (turtle-move radius)
        (turtle-turn (vector 0 angle 0))
        (let ((tx (vmul (vtransform (vector s (/ i n) 0) 
            (mrotate (vector 0 0 (sin (time))))) 3)))
        (pdata-set "t" (turtle-position) tx))
        (let ((tx (vmul (vector s (/ i n) 0) (sin (* (time) 0.1)))))
        (pdata-set "t2" (turtle-position) tx))
        (turtle-vert)
        (turtle-skip 1)
        (if (zero? (- i 1))
            0
            (loop (- i 1) angle)))

    (turtle-push)
    (loop n (/ 360 n))
    (turtle-pop))

(define (shape c n)
    (circle c (* 0.5 (+ 2 (sin (+ (gh 2) n)))) n)
    (turtle-skip (- (- (* c 2) 1)))
    (turtle-turn (vector 0 0 90))
    (turtle-turn (vector (* (sin (gh n)) 5) 0 (* (cos (gh (+ n 4))) 5)))
    (turtle-move 1)
    (turtle-turn (vector 5 0 0))
    (turtle-turn (vector 0 0 -90))
    (circle c (* 0.5 (+ 2 (sin (+ (gh 2) (- n 1))))) (+ n 1))
    (turtle-skip -1)
    (if (zero? n)
        0
        (shape c (- n 1))))

(clear)
;(clear-frame 0)
(backfacecull 0)
(clear-colour (vector 0.5 0.5 0.5))
(shinyness 100)
(specular (vector 1 1 1))
(texture (load-texture "hole.png"))
(multitexture 2 (load-texture "hole.png"))
(line-width 2)
(hint-multitex)
(define o (build-polygons 864 0))
(turtle-attach o)
(turtle-reset)

(grab o)
(pdata-copy "t" "t2")
(ungrab)

(define (update)
    (grab o)
    (turtle-reset)
    (shape 12 35)
    (recalc-normals 1)
    (ungrab))

(every-frame (update))