Throughout the years, Mr. Foy invented new systems as he needed them in order to improve the state of stage flying. Mary Martin benefitted from the "Inter-Related Pendulum," which "made spectacular highly controlled free flight possible." The system, however, needed a 40-foot ceiling to function, so, in 1958, Mr. Foy created the "Floating Pulley" for low-height houses. The "Track on Track" system followed in 1962, which allowed two operators to independently control the lift and movement of an actor.