New AI Can Learn a Game By Watching You Play, Develop Its Own Strategies to Beat You.
As it watches, [the computer] uses standard image-processing tools to recognise changes in the separate board squares and pieces of a game, while ignoring extra details like human hands. The videos allow the system to learn the rules by logging what the board looks like when a game has been won, and what count as legal moves. Having mastered the rules, the software plays the game by examining all possible moves and choosing those it deems most likely to lead to a win.
As you would expect, its performance depends on the complexity of the game. Connect 4 has few possibilities, making it very hard to beat the trained computer.
(via Computer watches you play a game, then beats you at it - tech - 10 July 2012 - New Scientist)