; Illustration of the graphic capabilities of zlisp.
; Alejandro Luque Estepa, 1999

(import "zlisp.LispMath") 
(import "zlisp.LispGraph") 

(defun spring nil
  (prog nil
	(do ((y 0 (add1 y))) ((> y height) t) 
	  (color 0.0 0.0 (/ y (* height 1.0))) 
	  (line 0 y width y) 
          ) 
	
	(do ((j 0 (add1 j)) 
	     (x (/ width 2)  (round (* (random) width))) 
	     (y (/ height 2) (round (* (random) height))) 
	     (r 100 (round (* (random) 60)))) 
            ((> j 10) "The End") 
	  (color 1.0 1.0 1.0) 
	  (do ((a 0 (+ a 0.01))) 
              ((> a (* 2 pi)) "Ok") 
	    (line x y 
		  (+ x (round (* r (cos a) (cos (* 6 a))))) 
		  (+ y (round (* r (sin a) (cos (* 6 a)))))) 
	    ) 
	  
	  (color 1.0 1.0 0.0) 
	  (do ((r2 0 (add1 r2))) ((greaterp r2 (quotient r 4)) "Ok") 
	    (circle x y r2) 
	    ) 
	  )
	)
  )

(msg "zlisp 0.1 Sample file." t
     "Write (spring) then switch to graphics mode and click on Eval All" t)