For all the innovations that hadn’t escape the multi-hyphenate and prolific inventor Leonardo da Vinci including the helicopter, the grenade, the floating dredger and even the spaghetti-making device, there was one that gnawed at his genius: a perpetual motion machine. It was a concept that attempted to achieve motion indefinitely without an external source of energy. This, according to all known laws of thermodynamics, is inherently impossible. It wasn’t until four centuries after his death when Neuchâtel engineer Jean-Léon Reutter fulfilled this pipe dream with the creation of the Atmos Clock. He designed an atmospherically driven clock that drew power from thermal expansion and contraction which by 1936 was then developed and produced by Jaeger-LeCoultre. The result was an undoubted triumph in chronometry that came astonishingly close to perpetual motion.