Curling is a sport in which players slide stones on a sheet of ice toward a target area that is segmented into four concentric circles. It is related to bowls, boules, and shuffleboard. Two teams, each with four players, take turns sliding heavy, polished granite stones, also called rocks, across the ice curling sheet toward the house, a circular target marked on the ice. Each team has eight stones, with each player throwing two. The purpose is to accumulate the highest score for a game; points are scored for the stones resting closest to the centre of the house at the conclusion of each end, which is completed when both teams have thrown all of their stones once. A game usually consists of eight or ten ends.
Players induce a curved path, described as curl, by causing the stone to slowly rotate as it slides. The path of the rock may be further influenced by two sweepers with brooms or brushes, who accompany it as it slides down the sheet and sweep the ice in front of the stone. "Sweeping a rock" decreases the friction, which makes the stone travel a straighter path (with less curl) and a longer distance. A great deal of strategy and teamwork go into choosing the ideal path and placement of a stone for each situation, and the skills of the curlers determine the degree to which the stone will achieve the desired result.