Rack 'n Roll was the game for the 2007 FIRST Robotics Competition season, announced on January 6, 2007. In it, two alliances of three teams each competed to arrange ring-shaped game pieces on a central arena element known as 'The Rack'. Robots Classes Robots fall under three different classes restricting their maximum weight and height. These classes are: Other restrictions Robots also must have a maximum starting footprint of 28" x 38" regardless of class. Robots may expand once the match has begun. The game manual includes other rules restricting various aspects of the construction of the robot that have been put in place for the purpose of safety and fairness. Field 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. Game pieces The game pieces in Rack 'n Roll are inflatable toroidal pool toys. There are 3 styles: Keepers, Ringers, and Spoilers. Keepers are tubes with lettering that are placed only during autonomous mode and, once placed, override any pieces placed later for scoring purposes. Ringers are undecorated tubes that are delivered onto the field either by human players via chutes, or are picked from the floor. Nine ringers of each color start on the field in the opposing team's start area (so the 9 blue ringers are in the red alliance's end zone, and vice versa). The other nine start behind the end wall, to be given out by human players. Spoilers are colored black, and cause the spider arm holding them to be ignored for scoring purposes. Spoilers can be removed or repositioned on the rack by robots multiple times. Each alliance starts with two spoilers, accessible by their human players. Game play Each match of Rack 'n Roll is 2