In a Pickle (card game) of or underneath a pile, the player then draws a card from the stack of unused cards to replenish their hand. The rule book encourages players to be creative when placing cards; one possible creative play is to place "universe" beneath "dictionary", as the word "universe" can be found in a dictionary. If a player cannot or chooses not to play a card, they may exchange up to three cards from their hand for the same number of cards from the pile of unused cards before ending their turn. Once the fourth card is placed in any of the four
Partition of a set into the connected components of the subgraph formed by the given set of edges. In this way, the lattice of partitions corresponds to the lattice of flats of the graphic matroid of the complete graph. Another example illustrates the refining of partitions from the perspective of equivalence relations. If "D" is the set of cards in a standard 52-card deck, the "same-color-as" relation on "D" – which can be denoted ~ – has two equivalence classes: the sets {red cards} and {black cards}. The 2-part partition corresponding to ~ has a refinement that yields the "same-suit-as" relation ~, which has