Pythagorean Cup, designed by Pythagoras over 2,500 years ago, still remains a popular practical joke.😁 There is a column in the middle of the cup, which in fact is a twisted pipe connected to the hole in the bottom. If you try to fill the cup over the certain level, Pascal’s principle of communicating vessels causes the liquid to run over the stem inside the column, creating siphon effect and draining the entire cup. The legend says that Pythagoras made this cup to punish friends who poured too