Perpetual Motion Machine
A perpetual machine is said to violate the laws of thermodynamics by generating enough energy to run forever on its own movements. Throughout the ages, fraudulent perpetual motion machines have proliferated. The most famous one is Charles Redheffer's: a machine so convincing that skeptics agreed to pay a large sum of money to expose him. As it turned out, all it took was removing some wooden planks from the device to find a belt that went through a wall where an old geezer was hiding—turning a crank with one hand and eating a loaf of bread with the other!