I beg to differ. According to your link, a Trebuchet is a type of catapult[5] that uses a rotating arm with a sling attached to the tip to launch a projectile. The image given is a regular catapult with the projectile resting in a bowl shaped holder carved into the launch arm. The spring mechanism in the image is different than I am accustomed to seeing, but, without the projectile sling on the arm, it is definitely not a Trebuchet.