How to build a Trebuchet (Catapult) | Brian's Science and Technology | Scoop.it
A Trebuchet (pronounced treb-oo-shay)  is a medieval siege engine that transfers gravitational energy into kinetic energy – similar to a playground see-saw.  In ancient times, it was used to launch (throw) projectiles including boulders, dead horses, and diseased bodies into or over castle walls ... http://wildernessarena.com/supplies/weapons/how-to-build-a-trebuchet-catapult-offense-defense