What is "sport stacking"

n. A sport in which competitors stack cups as quickly as possible.

Sport stacking (also known as cup stacking or speed stacking) is an individual and team sport that involves stacking plastic cups in specific sequences in as little time as possible. The cups are specially designed to allow for faster times. Participants of sport stacking stack cups in pre-determined sequences, by aligning the inside left lateral adjunct of each cup with that of the next. Sequences are usually pyramids of 3, 6, or 10 cups. Players compete against the clock or another player.

The governing body setting the rule is the WSSA (World Sport Stacking Association).