CLS : SCREEN 12 ZZ = 100 DO UNTIL ZZ = 1000 ZZ = ZZ + 10 WINDOW SCREEN (0, 0)-(ZZ, ZZ) I = 0 DO WHILE I < ZZ LINE (I, 0)-(I, ZZ), Z LINE (0, I)-(ZZ, I), Z I = I + 1 LOOP Z = INT(RND(1) * 15) + 1 IF INKEY$ <> "" THEN EXIT DO LOOP