10 CLS 
20 CROFF 
30 a=PORT i(0)
31 b=PORT i(1)
32 c=PORT i(2)
33 d=PORT i(3)
35 POS 0,10
40 PRINT TAB (1);a;TAB (6);b;TAB (11);c;TAB (16);d
45 PORT o(6,a)
50 GOTO 30