In theory, Formula 1 is a contest of speed. In practice, it is often a contest of interpretation. Ahead of the 2009 season, the FIA introduced sweeping aerodynamic regulation changes intended to reduce downforce and slow the cars. Most teams complied conservatively, simplifying their rear bodywork in line with the spirit of the rules. One newly formed team examined the wording more closely. They identified a regulatory ambiguity and implemented X, a design that allowed airflow to expand through a secondary channel at the rear of the car, significantly increasing downforce while remaining technically legal. That season, Brawn GP dominated the early races, and their driver Jenson Button secured the World Championship. Id X [2 words].