catapult is a ballistic device used to launch a projectile a great distance without the aid of explosive devices—particularly various types of ancient and medieval siege engines. Although the catapult has been used since ancient times, it has proven to be one of the most effective mechanisms during warfare. many skill-Up mechanisms and scientific knowledge are applied in catapults, so children can grab many skills and physic knowledge in this product (Skill-Up Toys). they are able to build own catapult, then they can play several game via this catapult.