310 X=0:Y=0
320 P2=PEEK(56320)
321 IF (P2 AND 1)=0 THEN Y=-4
322 IF (P2 AND 2)=0 THEN Y=+4
323 IF (P2 AND 4)=0 THEN X=-4:XB=2
324 IF (P2 AND 8)=0 THEN X=+4:XB=0
330 IF X=0 AND Y=0 THEN 320
340 POKE 2040,32+XB
345 GOSUB 500
350 POKE 2040,33+XB
355 GOSUB 500
400 GOTO 310
500 BW=BW+X
501 CW=CW+Y
505 IF BW>344 THEN BW=0
506 IF BW<0 THEN BW=BW+344
507 IF CW>242 THEN CW=0
508 IF CW<0 THEN CW=CW+242
510 BH=INT(BW/256):BL=BW-BH*256
520 POKE V+0,BL
521 POKE V+1,CW
530 POKE V+16,BH
560 FOR W=0 TO 50:NEXT
600 RETURN