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Shape Rule
(lemmy.blahaj.zone)
[A person offering a second person a Klein bottle. The second person rejects the Klein bottle. They have a plate of regular three dimensional shapes in front of them. They have picked up a rectangular prism on their fork. In the upper left corner is the text: "No! A responsible adult says no to non-orientable shapes"]
I think that's called a Boy's Surface. There is a different animation of the same object in the Wikipedia article. It's a disk with a mobius strip glued to its edge, but most articles get too mathsy too quickly for me to understand, so that's all the information I can provide :3