All the cards that are not in any meld are referred to as deadwood. It is not allowed to intersect melds, meaning that if a set and a run share a common card, only one of them will be counted as a meld, and the rest of the cards in the other meld are deadwood. The sets are formed of three or four cards of the same rank. The runs refer to several cards in sequence, typically more than three, and all of the same suit.
There are two types of melds, runs and sets.
