On a mild autumn day in 2016, the Hungarian mathematician Gábor Domokos arrived on the geophysicist Douglas Jerolmack’s doorstep in Philadelphia. Domokos carried with him his suitcases, a bad cold, ...

Geometry also predicted that if you fragmented a flat surface randomly, it would break into rough rectangles, and if you did the same in three dimensions, it would produce rough cubes. But for any of ...