Pythagoras Cup

A Pythagorean cup, also known as a Pythagoras Cup, Greedy Cup, Cup of Justice or Tantalus Cup, is a practical joke device in a form of a drinking cup, credited to Pythagoras of Samos.

(from Wikipedia)

This cup, if filled to the ring will hold the liquid happily, however if filled higher than the ring, a tube hidden on the inside will syphon the entire contents out onto the floor!

In this design, the tube is about 4mm in diameter and takes less than a minute to empty the cup. Here is a loop of the cup emptying from the line (sped up about 2x):

I printed this one with Overture Silk Copper with a .6 nozzle and .28 layers. My print was about 7hrs. I highly recommend aligning the seam in the slicer.

I included a split sectioned view as well. I haven't printed that yet, but will post a pic of that once I get a chance. I thought this was a nice inclusion for those wanting to talk about this with kids and explain what's happening.

Full credit to the original designer (Pythagoras) - I'm not sure if he still has copyright on the design, but I'm going to chance it ;-)