( Sprite low-level JCB 15:23 11/15/10) : vga-line@ begin vga_line @ vga_line @ over xor while drop repeat ; : waitblank begin vga-line@ d# 512 = until ; : sprite! ( x y spr -- ) 2* cells vga_spritey + tuck ! 2- ! ; : hide \ hide all the sprites at (800,800) d# 8 0do d# 800 dup i sprite! loop ;