Mathematics not trademarkable: http://trademarkblog.kluweriplaw.com/2021/12/06/gomboc-3-the-final-decision/
Somehow I missed this, but late last year the Supreme Court of Hungary ruled on a lawsuit asking to trademark the Gömböc (https://en.wikipedia.org/wiki/G%C3%B6mb%C3%B6c), a 3D convex shape that, with only a single stable position, rights itself when placed on a flat surface. (Like a Weeble, but unweighted.) The answer was no: as "an answer given to a question of mathematics" with a shape "necessary for the Gömböc to self-right", it could not be trademarked.
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