I have a square plaque i want to cut keyhole-like holes into it. I have the keyhole as a seperate object. I want to be able to hang the plate on the wall with screws. Should i try to merge the two objects, or how would you make a keyhole into the plate? It has to be hollow behind the edges of the keyhole for the screw to hold the plaque into place. It had been nice if i could invert the keyhole and use it as "hole"