Rack 'n Roll is the game for the 2007 FIRST Robotics Competition season, announced on January 6, 2007. In it, two alliances of three teams each compete to arrange toroidal game pieces on a central arena element known as 'The Rack'. The Rack 'n Roll field is dominated by 'The Rack', a large metal contraption with three levels of hanging metal bars, with each level having 8 arms evenly spaced in an octagonal manner. Each arm (known as a 'spider leg') has space for two game pieces. Any more pieces placed on a spider leg beyond the first two are ignored for scoring purposes. At the beginning of the match, the rack is arbitrarily translated or rotated within three feet of the center of the field in order to give some randomness and to encourage autonomous modes that do not depend on dead-reckoning. At the top of the Rack are four green-colored lights above the 1, 3, 5, and 7 legs to aid in autonomous-mode tracking. Each match of Rack 'n Roll is 2 minutes 15 seconds long, divided into three segments. The first segment is a 15 second autonomous period, where robots may attempt to place keepers onto the rack without human input. Once autonomous mode is complete, any keepers not already on the rack are no longer valid for scoring. The second segment, the teleoperated mode, is 2 minutes long, during which robots are operated by the drivers and may roam anywhere on the field. In the final 15 seconds, the end game, robots may not enter their opponent's end zone, but all other rules remain the same from the teleoperated period. Though the head referee may pause the game between the autonomous period and the teleoperated period, the end game follows directly after the teleoperated period.