We've Got a Catapult in the Works

So our engineering project is to design and build catapult. This is our catapult in the works. Nothing is screwed or secured, but this is the rough shape. Surgical tubing will be stretched between the towers and the swing arm will be pulled back against the tubing. Our little pulley thing will be used to pull down the swing-arm. I don't feel like typing a whole lot more, just because I'm lazy and I hurt one of my fingers, sorry. Enjoy the picture!