An intriguing layer of strategy is added when players try to "knock" when they think their opponent has a higher total value of unmatched cards than they do. Another popular variant is Indian Rummy, in which players musgame download freet create at least two sequences, one of which must be a pure sequence (i.e., devoid of jokers), and frequently use two decks of cards. Players must traverse several decks and possible melds in this version, which adds complexity and strategic depth. Additional variants include Canasta, which combines aspects of Rummy with special scoring rules and meld requirements, and Kalooki, which adds wild cards and permits more complex gameplay.