A tetrahedron is the simplest Platonic solid. Mathematicians have now made one that’s stable only on one side, confirming a decades-old conjecture.

At the heart of the Giza Plateau, three massive pyramids rise from the desert floor in near-perfect alignment. The Great ...

A variation of a puzzle called the “pick-up sticks problem” asks the following question: If I have some number of sticks with ...