How to use - 'Perpetual' motion machine

Move one of the model's 'arm' downwards without forcing to start the movement. Principle: A ball or a liquid moves thanks to the force of gravity and its weight pulls the wheel which, by turning, pulls up another ball/liquid, and so on in a theoretically perpetual way. As it is almost impossible to build a completely balanced model, the level of the movement varies according to the part moved.