A catapult is a system that is used to    
throw a projectile large distances. Catapults
are also siege engines that use a arm to hurl
missiles and medieval warfare.
            Catapults can be classified according to
the physical concept used to store and release
the energy required to throw the projectile.
Initially a catapult was designed to toss spears
and other warfare at a low trajectory.
        Common objects that were used for
ammunition in catapults were stones, pot of burning oil, burning debris, boulders, and other dangerous objects.