Pythagoras cup was comonly used during siege of the island Samos, when water (and the wine) were rationed. Cups allows equal divide of the drinks and if somebody was greedy and pour himself more, all content of the cup poured out and recived nothing. Here is a quick video showing how does it works and also small experiment. 1) What do you think about Pythagoras cup? 2) Would you like to play with one? 3) Knowing that you can buy it as a gift on Samos island would you consider this location as holiday spot? Sources: https://www.geekipodrozniki.pl/kubek-pitagorasa/