Launch It: the Paper Catapult. : 6 Steps (with Pictures) - Instructables
Catapults were invented about B. These Greek engineers first constructed a small machine, called the Gastraphetes, sort of a crossbow. However, after they found out how good the smaller Gastraphetes were, they made a bigger one and put it on a carriage to transport it and added a windlass to cock the heavier machine. Some physical barriers prevented the Gastraphetes from getting any larger. So in the mid-forth century B.