On a table in front of you is a chessboard, its pieces frozen midway through a game. It's white's turn to play. How long would it take you to find white's best move? Not a good move or even a great ...

But last weekend, it lost a game of chess. Not to a human grandmaster or even to some other fancy AI. It lost to an Atari 2600 that first appeared in the 1970s and can only calculate one or two chess ...