The Gastraphetes was a type of compound bow used about 400BC by the ancient Greeks and Macedonians. Heron of Alexandria, the great inventor describes it in Belopoeica, and there exists also a description by the 3rd century BC engineer Ctesibius. The name gives away its western translated moniker: the Belly Bow. Once you locked the string onto the firing frame, your leaned it against something like the ground or a tree and leaned on it, with your belly of pushed until it drew back and pulled the string tight. Then you loaded an arrow into a slotted holding space and all you had to do to fire the Gastraphetes was pull a lever that released the string. It fired regular arrows.