Perpetual Motion Machine

"Perpetual Motion Machine" - Perpetuum Mobile, scheinbar von selbst laufende Maschine.
Perpetual motion machines are a class of hypothetical machines which produce useful energy "from nowhere." The existence of a perpetual motion machine is generally accepted as being impossible according to current known laws of physics.
Nevertheless, Bela Fleck describes the banjo as kind of a perpetual motion machine. Hearing him play almost makes one believe it.