Pythagoras' Cup of Justice is a kind of cup attributed to Pythagoras of Samos, which looks like an ordinary cup for drinks from the outside, but has a special device inside.

The characteristic of the cup, which is referred to as Pythagoras' cup of justice, is that there is a line on the cup. When you fill the glass up to that line, you can use it as a normal glass. But if you cross that line, things change.

If you cross that line in the glass even a little bit, the siphon effect is activated in the glass and all the water in the glass is poured out from the bottom. If you cross the line, you will lose not only the top of the line but everything you have. You need to know very well where you should stand. If you don't, you will lose everything you have.

How many things a glass can tell us.