The aim of Pyramid is to remove all the cards to a single pile by making pairs that add up to 13.
The game starts with a pyramid of cards dealt face up and overlapping. 1 card at the top, 2 on top of that, 3 next and so on until the bottom row has 7 cards. The remaining cards are the stock. Cards are dealt from the stock onto an adjacent waste pile. Any matched pairs are placed on a foundation pile on the right.
To play Pyramid you turn over the stock one card at a time and try to make pairs of cards that add up to 13. The King is worth 13, and is removed on his own, the Queen and Jack are 12 and 11 respectively. All other cards are face value. The pairs are: "King", "Ace + Queen", "2 + Jack", "3 + 10", "4 + 9", "5 + 8" and "6 + 7".
Any card in the pyramid that doesn't have a card overlapping it is available for play, as is the top card of the waste pile. When you match 2 cards they are placed on the foundation. By default you can only click through the stock once.
The game is won when all the cards from the pyramid have been matched. If you have been through the stock and can make no more matches, the game is over.