Players must create "canastas," or melds of seven or more cards, using two decks of cards. When played in pairs, the game places a strong emphasis on cooperation, which can make individteen patti modelual strategies more difficult. Players need to think about how their actions affect their partner's ability to form melds in addition to their own hands. Effectively controlling the use of wild cards is a major Canasta challenge. When creating melds, wild cards can be used in place of any other card, but there are restrictions on how many can be used in a single meld.
