Pythagoras Cup

The Pythagoras Cup is a practical-joke device that is used to demonstrate greed.

It’s a siphon in the middle of the cup, basically the same as a toilet. It behaves like a normal cup in the beginning. Once liquid is filled above the flow line, the siphon begins flowing until all the liquid is drained out.

This demonstrates greed, as your experience a big loss if you are too greedy.

Curiously, I looked into the working mechanism behind a siphon and it seems that this is still under contention. It’s funny to think that we use and rely on these thing everyday, despite not being to adequately explain how the physics is supposed to work out.