If you have a few chess sets at home, try the following exercise: Arrange eight queens on a board so that none of them are attacking each other. If you succeed once, can you find a second arrangement?

Have a good mind for computational problem-solving? Fancy netting a cool $1 million for your efforts? Then the University of St. Andrews and the Clay Mathematics Institute sure have the competition ...

The original version of this story appeared in Quanta Magazine. When Covid-19 sent people home in early 2020, the computer scientist Tom Zahavy rediscovered chess. He had played as a kid and had ...