The proof, known to be so hard that a mathematician once offered 10 martinis to whoever could figure it out, uses number ...

How many triangles can you count in this image? It’s harder than it looks and bound to baffle even the sharpest of brains for ...

When counting squares in a grid, don’t stop at the smallest boxes; the bigger ones are hiding too. The rule is simple: In an n × n grid—where n is the number of squares both horizontally and ...

Synchronization abounds in nature: from the flashing lights of fireflies to the movement of fish wriggling through the ocean, ...