There are two main defensive strategies: zone defense and man-to-man defense. In a zone defense, each player is assigned to guard a specific area of the court. In a man-to-man defense, each defensive player guards a specific opponent. Man-to-man defense is generally preferred at higher levels of competition, as it is intuitively easier to understand and avoid mismatches between players who play different positions. However, zone defenses are sometimes used in particular situations or simply to confuse the offense with an unexpected look. Offensive plays are more varied, normally involving planned passes and movement by players without the ball. A quick movement by an offensive player without the ball to gain an advantageous position is known as a cut. A legal attempt by an offensive player to stop an opponent from guarding a teammate, by standing in the defender's way such that the teammate cuts next to him, is a screen or pick. The two plays are combined in the pick and roll, in which a player sets a pick and then "rolls" away from the pick towards the basket. Screens and cuts are very important in offensive plays; these allow the quick passes and teamwork which can lead to a successful basket. Teams almost always have several offensive plays planned to ensure their movement is not predictable. On court, the point guard is usually responsible for indicating which play will occur. Defensive and offensive structures, and positions, are more emphasized in higher levels in basketball; it is these that a coach normally requests a time-out to discuss.