Well that was little tricky. First i had it so that the blue block would go up and down using the gravity, but i couldn't get it to scroll right when you go up and down. So instead of having gravity applying to the blue square i made it so that gravity does not affect the blue square but inverses gravity and applies it to everything else in the world.

thanks I now try to persuade the world around them instead of the dan players he should stay in the middle .. The problem now is that with my green border on foot rpg siene kicks and crashes xD thank you again for serving tip