Pythagorean Dribble Glasses
The diagram shows how a Pythagorean cup works. It's a thinking person's dribble glass, sort of. The cup, pan, and ladle in the photo is a yuza no ki. Both are gadgets used for teaching moderation.
The yuza no ki is in the Ashikaga District, 足利郡, in the Tochigi Prefecture. It hasn't been since around 1896. Ashiga District, that is. Not officially.
The cup might be.
It's a learning tool. Empty, it's tilted. Pour a little water in, and it goes upright. Pour in more, and it tilts again.
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