Forty Thieves is a card game for one player. Many "Patience" card games, as they are called, are built on variations of Solitaire.
Forty Thieves requires the solo player to discard all of his or her cards, moving them from the tableau to the foundations. A tableau is made up of piles of cards, which must be arranged in a specific order and moved under specific rules.
Step 1: Set up the game
Lay out 40 cards in 10 tableau piles of four cards each. They should be facing up and fanned out, meaning that they overlap each other and all cards can be seen. There are eight foundation piles, which start blank, and one empty discard pile to begin.
Step 2: Build the foundation piles
According to suit, move the cards one at a time, building the foundation piles according to the suit of the cards. The top card of each tableau pile and the top card of the discard pile are the only cards which are accessible. Foundation piles begin with the ace and end with the king.
Step 3: Deal cards as needed
The remaining 12 cards serve as the deck from which cards are drawn. If they are not used, they go to the discard pile.