A projectile is then set in a cradle at the long end of the arm so when the arm is released, it snaps back into place, hurling the rock forward. Mars I, the first catapult created for this project, was a Bent Wood machine. Records set by Bent Wood catapults during the National Catapult Contests include the Rebelorum machine, built by students at Pascagoula High School in Pascagoula, Mississippi, throwing a one-pound spear 668 feet, three inches in 1974, Horologium Tintinnabulum, built by students at Mauston High School in Maustin, Wisconsin, which hurled a ten-pound rock 96 feet, 8 inches, in 1975, and Machina Gigantum, built by students of Ben Davis High School in Indianapolis, which hurled a one-pound rock 186 feet, three inches, in 1977.