The Forty Thieves card game is a particularly difficult variant of classic solitaire requiring you to build 8 foundations of cards instead of 4 (from ace to king of the same suit). The difficulty comes from the fact that you can only play the top card of each tableau as well as the one from the stock. Fortunately, there is also an easy mode in which you can move cards of the same suit built down as a unit as well as reuse the stock pile. Get ready for long games that last an average of 15 good minutes.
