Has any one made castle walls out of rice krispies before? I wanted to make them as more of a back drop to a carriage cake. I plan on making an 8in round center cake and a rice krispie wall extending frome each side of that cake on a 2ft X 2ft board. I have pvc to attach to the board for support of the walls, I'm just worried the fondant on the walls might fall down. Any advice would be greatly appreciated.