1 G=1:FORV=0TO4:GOSUB13:FORU=0TO4:[L+U+V*5]=0:GOSUB12:NEXT:NEXT
2 FORU=0TO4:GOSUB14:FORV=0TO4:GOSUB12:NEXT:NEXT
3 GOSUB15:FORU=0TO4:V=U:GOSUB12:NEXT
4 GOSUB16:FORU=0TO4:V=4-U:GOSUB12:NEXT
5 W=200:FORY=0TO4:FORX=0TO4
6 A=X+Y*5:C=[L+A]:IFC<WAND[J+A]>0W=C:U=X:V=Y
7 NEXT:NEXT
8 A=U+V*5:D=[J+A]
9 FORY=15TO22:LC0,Y:?"             ":NEXT
10 LC0,15:?"CPU erase=";D:[J+A]=0
11 LRUNFILE()-1
12 A=U+V*5:[L+A]=[L+A]+([K+A]+S)*E:RETURN
13 E=1:S=0:Y=V:FORX=0TO4:GOSUB17:NEXT:RETURN
14 E=1:S=0:X=U:FORY=0TO4:GOSUB17:NEXT:RETURN
15 E=1:S=0:FORX=0TO4:Y=X:GOSUB17:NEXT:RETURN
16 E=1:S=0:FORY=0TO4:X=4-Y:GOSUB17:NEXT:RETURN
17 N=[G*25+X+Y*5]:IF!NE=0
18 IFN=-1S=S+1
19 RETURN