Leonardo da Vinci Catapult Kit

Leonardo Da Vinci developed a number of designs that were well before their time. His vision of vertical flight with his spiral helicopter, paddle wheel-powered vessels, and the early armored car may have been laughable in his day, but were the stepping stones for today's MV-22 Osprey, turbine-powered Ticonderoga-class cruisers, and M1 Abrams tank (and their analogs from other nations of course).