100 E$=CHR$(27):C=INT(X/6):BX%=INT(X-C*6):R=INT(Y/8):BT%=INT(Y-R*8):PRINT E$"P";:PRINT@(40*R+C),"";:B%=NOT(PEEK(65516+BX%)):CALL 30300:PRINT E$"Q":T%=2^BT%:D%= B% AND T%:IFD%<>0 THEN P=-1:RETURN:ELSE P=0:RETURN