+(define (make-asteroids n)
+ (define (xy n r)
+ (let ((n2 (- (random (* n 2)) n)))
+ (cond ((and (< n2 r) (>= n2 0)) r)
+ ((and (> n2 (- r)) (< n2 0)) (- r))
+ (else n2))))
+
+ (cond ((= n 0) '())
+ (else
+ (cons (list (xy max-x 20) (xy max-y 20) 0 1 1) (make-asteroids (- n 1))))))
+
+(let ((asteroids (make-asteroids 2))
+ (ship '((x . 0) (y . 0) (angle . 0) (moving . #f))))