You are in a room with no exits or ways to get out the walls and ceiling are made of titanium (don't ask how you got in) all you have is a table and a mirror how do you get out?
A catapult is not a device but it is a term. A catapult is any device used to launch an object a far distance. Billy has a Trebuchet, a Magonal, and a Ballista.
Hrm, well my answer seems to work just as well seeing as you didn't specify that they were or weren't the same size. It isn't the intended answer but it isn't completely wrong either.