Tilings and tessellations are such an interesting area of mathematics. They seem so simple that everything should have been discovered already, and yet new fundamental questions are raised every year!
In this case, researchers wondered about "soft" tilings, i.e. tilings with as few corners as possible and are entirely "rounded" elsewhere. It turns out they are everywhere in nature, both in 2D and 3D. And you can have tilings of three-dimensional spaces that have no corners at all!
https://www.reviewertoo.com/tessellation-revelation/
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