Remove score once.

Hello, (source : http://www.greenfoot.org/scenarios/12962) I've been trying to make a system that grants 10 points (balance points) once a crate makes contact with a balance board, I've got this kinda working with a boolean like so ; Note : i've been trying to use diffrent methods ( isTouching / Intersecting ) for testing purposes. The problem with this code is that if one crate makes contact with a balance board, it will take up all the ''slots'' ( the 8 booleans), and add X points till all the booleans are used up. Sigh. I've been trying to think of a way to add points once if a crate makes contact with a balance board, and than remove those points once that crate no longer makes contact with the balance board. Do I need to make multiple Crate2 classes, give every crate an unique ID ? Any help would be greatly appreciated. Sincerly.