10 DIMB(7):FORI=0TO7
 20 B(I)=INT(2^I):NEXT
 30 F=1200:L=PEEK(133)+256*PEEK(134)-1
 40 FORI=FTOL:FORJ=0TO7
 50 POKEI,B(J):X=PEEK(I)
 60 IFX<>B(J)THENPRINT:PRINT"POKED";B(J);"GOT";X;"AT";I:STOP
 70 NEXTJ
 80 PRINTCHR$(13);I;
 90 NEXTI:PRINT
 100 FORJ=0TO7:PRINT"BIT =";J
 110 FORI=FTOL:POKEI,B(J):NEXTI
 120 FORI=FTOL:X=PEEK(I)
 130 IFX<>B(J)THENPRINT"POKED";B(J);"GOT";X;"AT";I:STOP
 140 NEXTI,J:PRINT
 150 PRINT"INVERTING"
 160 FORJ=0TO7:B(J)=255-B(J):NEXTJ
 170 PRINT:GOTO40
 180 END