#zxspectrumbot
10 BORDER 1: PAPER 1: INK 5:POKE 23624,13: CLS 
20 LET a=192:FOR i=0 TO 7:POKE USR "A"+i,a:POKE USR "B"+7-i,a:LET a=INT (a/2):NEXT i
30 PRINT CHR$ (144+RND);: GO TO 30