Now I understand how it works, but I have one more question, can pfread be used to check specifically the top row of the playfield, instead of a single pixel at a time, I want to use it for sort of collision detection with the top row in particular but no for stopping the character from going through it, instead I want to use it to trigger a goto another screen, well actually not to another screen but to the previous one, kind of like going back and forth between 'em, do you think that using a counter that adds 1 every time you go to a new screen and substracts one when you return to the previous one, for cycles counting, or RAM saving?