Perpetual motion, definition:

Perpetual motion describes any motion that continues indefinitely without any external source of energy, which is impossible due to energy loss (e.g. friction). Machines achieving this would at the very least violate the first law of thermodynamics (energy can't be created in an isolated system; the output power can't be bigger than the input power).

Here, a few machines will be described that seem to work and, in theory, even produce energy - for free! Find the mistakes...

1.)  The Arabic Wheel **

2.)  Reno’s Induction Apparatus ***