- (draw-vertex v1 #:texture-coord '(0 0))
- (draw-vertex v2 #:texture-coord '(1 0))
- (draw-vertex v3 #:texture-coord '(1 1))
- (draw-vertex v4 #:texture-coord '(0 1))
+ (draw-vertex v1 #:texture-coord (car texture-coord))
+ (draw-vertex v2 #:texture-coord (list (caadr texture-coord) (cadar texture-coord)))
+ (draw-vertex v3 #:texture-coord (cadr texture-coord))
+ (draw-vertex v4 #:texture-coord (list (caar texture-coord) (cadadr texture-coord)))