450 IF board(f,g)=play AND board(f-1,g+1)=play AND board(f-2,g+2)=play AND board(f-3,g+3)=play THEN winflag=4:GOTO 550
450 IF board(f,g)=play AND board(f-1,g+1)=play AND board(f-2,g+2)=play AND board(f-3,g+3)=play THEN winflag=3:GOTO 550