Creates "The Matrix" rain effect in MSX BASIC

matrix.bas

10 SCREEN 1:COLOR 12,1,1:KEY OFF:WIDTH32:A$="       THE MATRIX HAS YOU!        "
20 B=BASE(6):C=16*15+0:VPOKE B+8,C:VPOKE B+9,C:VPOKE B+10,C:VPOKE B+11,C:GOSUB 100
30 LOCATE X1%,Y%:IF Y%<>11 THEN PRINT CHR$(RND(1)*221+33);:LOCATE X2%,Y%:PRINT" ";ELSE PRINTMID$(A$,X1%+1,1);
40 Y%=(Y%+1) MOD 23:IF y%=0 THEN GOSUB 100
50 GOTO 30
100 X%=0:X1%=INT(RND(1)*32):X2%=INT(RND(1)*32):RETURN