If there are nine people in a room and every person shakes hands exactly once with each of the other people, how many handshakes will there be? How can you prove your answer is correct using a model ...

Rubik’s Cube-solving robots are far from a new idea. In fact, while the human record holder can solve a cube in just 4.22 seconds, the fastest cube-solving robot does it in a little over half a second ...

The first time I was allowed to travel beyond the Iron Curtain and visit the West was in 1980. I ventured from Hungary to New York for the International Toy Fair, where a puzzle I had invented was ...