10 REM ** "D:HEADSUP.BAS" **›20 REM ** A MACHINE LANGUAGE PROGRAM **›30 REM ** THAT YOU CAN RUN **›40 REM ** STANDING ON YOUR HEAD **›50 REM›60 GRAPHICS 0 : PRINT›100 POKE 755, 4›110 OPEN #1,4,0,"K:"›120 GET #1,K›130 PRINT CHR$(K);›140 GOTO 120››