SACHA PFEIFFER, HOST:

Good morning. I'm Sacha Pfeiffer with big news for geometry enthusiasts. A hobbyist in the U.K., David Smith, has come up with a brand-new 13-sided shape. It's called the hat because it kind of looks like a fedora. And it's what's known as an Einstein tile. That means unlike every other shape, if it's laid out and slotted together over and over again, it doesn't easily repeat itself. Who says they don't like math? It's MORNING EDITION. Transcript provided by NPR, Copyright NPR.