variable paint-x X 2/ paint-x ! variable paint-y Y 2/ paint-y ! variable paint-color 2 paint-color ! : paintx+ paint-x @ + X mod paint-x ! ; : painty+ paint-y @ + Y mod paint-y ! ; : paint-xy begin-line-io cell field paint-color @ paint-x @ paint-y @ write-point end-line-io xvds ; : Paint-up -1 painty+ paint-xy ; press W "Paint next location up." : Paint-down 1 painty+ paint-xy ; press Z "Paint next location down." : Paint-left -1 paintx+ paint-xy ; press A "Paint next location left." : Paint-right 1 paintx+ paint-xy ; press S "Paint next location right."