Pairing game type. 2 decks. Unlimited redeals.
Move all the cards to the foundations.
Deal cards from the stock two at a time. Pairs of cards of the same rank can be moved to the foundation. Once the stock is empty, the two piles are flipped over and create a new stock.
The game is won once all cards are moved to the foundations. Unlimited redeals are allowed, so all games should turn out eventually.