of bounds, goaltending and backcourt violation. Half-court play The majority of streetball games are played 3-on-3 on a half court. Special rules have been developed for half-court play: At the beginning of the game and after each made basket, play begins at the top of the key. A "checking" system is used to ensure that both teams are ready to begin play. This involves the offensive player saying "check" while throwing the ball to his defender. The defender then makes sure their team is ready and then throws the ball back to begin play. If the ball goes out of bounds during play, the ball can either be checked from out of bounds near where the ball went out or at the top of the key, depending on the rules established before the game. FIBA recently had to add the "check clock" rule into play in their streetball tournaments due to some players taking excruciatingly long amounts of time to check the ball, interrupting the flow of play. This "check clock" means that when the defending player has been checked the ball, he has to return it within 5 seconds. The "12-second shot clock" rule can be implemented as well to prevent longer possessions. (used in streetball tournaments) If the defending team gains possession of the ball, they must "clear" the ball past the three-point line before they can score a basket. This does not need to be at the top of the key and no checking is required. Sometimes in a half-court game, a "winner's ball" or "make it, take it" rule is used. This means that if a team scores will gets the ball again on offense; that team could end up never getting the ball on offense if the other team scores on every possession. Game structure A common feature of street basketball is the pick up game. To participate in most streetball games around the world, one simply goes to an outdoor court where people are playing, indicates a wish to participate, and from all the players who were at the court before one has played, two players acting as "captains" will get to pick their team out of the players available and play a game. Generally, the team captains alternate their choices, but different courts have differing rules in regards to player selection. Many games play up to 7, 11, 13, 15, or 21 points