- (gl:with-pushed-matrix
- (gl:translate (* (getf turtle :xcor) *patch-size*) (* (getf turtle :ycor) *patch-size*) 0)
- (gl:rotate (getf turtle :heading) 0 0 -1)
- (gl:call-list *turtle-list*)))
+ (mapcar
+ (lambda (x-modification y-modification)
+ (gl:with-pushed-matrix
+ (gl:translate (* (getf turtle :xcor) *patch-size*) (* (getf turtle :ycor) *patch-size*) 0)
+ (gl:translate x-modification y-modification 0)
+ (gl:rotate (getf turtle :heading) 0 0 -1)
+ (gl:call-list *turtle-list*)))
+ (list 0 (1- (world-width-in-pixels)) (- (1- (world-width-in-pixels))) 0 0)
+ (list 0 0 0 (1- (world-height-in-pixels)) (- (1- (world-height-in-pixels))))))