Scramble contains instructions for play in the listing and is a fairly simple game of logic that nevertheless is quite challenging. To see if you can improve, or to challenge an opponent, there is a counter on the bottom right of the screen. The best time is transferred to the bottom left and will be updated until System Reset is pressed.
The program is interesting in that it uses Inverse characters in Graphics 2, something which you cannot normally get. This is achieved by transferring the character set to RAM and redefining the characters in lines
200-260. Rather than writing data for each of the characters, the Inverse is achieved by POKEing the difference between 255 and the data of the original character at the time the characters are transferred. Some characters cause problems due to the fact that they do not have 'borders' and these need to be specially defined. The letter 'M' is a case in point and is redefined in line 250 with Data from line 260. Try this technique in your own programs, the result is quite pleasing and gives much more impact.
A WORD OF WARNING. The program contains a routine which re-runs the program on System Reset (courtesy of Norwich User Group) and the Break key is disabled. SAVE A COPY OF THE LISTING BEFORE YOU RUN IT. If you don't, there is no way to LIST the program once it has been RUN. If you use TYPO to check the listing, the table given is for the listing as printed and TYPO should be used before the program is first RUN. If you wish to check the listing otherwise, it is suggested that line 6 is deleted and then reinstated once the program is running correctly.