;;; Scheme Recursive Art Contest Entry
;;;
;;; Please do not include your name or personal info in this file.
;;;
;;; Title: Anathema
;;;
;;; Description:
;;;   <Consciousness, Existence
;;;    Simulation, Consciousness
;;;    Existence, Simulation>

(define (draw)
	(speed 0)
	(hideturtle)
	(pendown)
	(define size 6) ;change size to anything you want
	(dragon_build '(f x) size)
)

(define (dragon_build turtle_instructions n)
	(if (= n 0) 
		(recursion turtle_instructions) 
		(dragon_build (helper turtle_instructions) (- n 1))
	)
)

(define (helper temp)
	(cond
		((null? temp) nil)
		((eq? (car temp) 'x)
			(cons 'x (cons '+ (cons 'y (cons 'f (helper (cdr temp)))))))	
		((eq? (car temp) 'y)
			(cons 'f (cons 'x (cons '- (cons 'y (helper (cdr temp)))))))	
		(else (cons (car temp) (helper (cdr temp))))
	)
)

(define (recursion ces)
	(cond
		((null? ces) nil)
		((eq? (car ces) 'f) 
			((forward 20) (recursion (cdr ces))))
		((eq? (car ces) '+)
			((right 90) (recursion (cdr ces))))
		((eq? (car ces) '-)
			((left 90) (recursion (cdr ces))))
		(else (recursion (cdr ces)))			
	)	
)

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