The Trebuchet In Action

Above you see a small trebuchet in mid-swing. The counterweight drops, pulling the arm through a swing that propels the projectile around in a circle, and the sling it is in would release it as soon as it reaches the top of its arc.

Trebuchets are extremely accurate devices; once aimed at a target, it is possible to (assuming the same projectile weight) repeatedly hit the same target over and over. A trebuchet could fling a projectile several hundred yards and have all its projectiles land within a couple feet of one another. And, as noted, what is pictured above is a small trebuchet; in medieval times, they were used to fling dead livestock over the walls of besieged castles to rot and give the people inside diseases, in one of the earlier appearances of biological warfare. And trebuchets scale upward nicely, making it possible to throw with them any number of objects, including: