sport and football code of American football. Camp was central to several more significant rule changes that came to define American football. In 1881, the field was reduced in size to its modern dimensions of 120 by 53 yards (109.7 by 48.8 meters). Several times in 1883, Camp tinkered with the scoring rules, finally arriving at four points for a touchdown, two points for kicks after touchdowns, two points for safeties, and five for field goals. Camp's innovations in the area of point scoring influenced rugby union's move to point scoring in 1890. In 1887, game time was set at two halves of 45 minutes each. Also in 1887, two paid officials—a referee and an umpire—were mandated for each game. A year later, the rules were changed to allow tackling below the waist, and in 1889, the officials were given whistles and stopwatches. The last, and arguably most important innovation, which would at last make American football uniquely "American", was the legalization of interference, or blocking, a tactic which was highly illegal under the rugby-style rules. Interference remains strictly illegal in both rugby codes. The prohibition of interference in the rugby game stems from the game's strict enforcement of its offside rule, which prohibited any player on the team with possession of the ball to loiter between the ball and the goal. At first, American players would find creative ways of aiding the runner by pretending to accidentally knock into defenders trying to tackle the runner. When Walter Camp witnessed this tactic being employed against his Yale team, he was at first appalled, but the next year had adopted the blocking tactics for his own team. During the 1880s and 1890s, teams developed increasingly complex blocking tactics including the interlocking interference technique known as the Flying wedge or "V-trick formation", which was developed by Lorin F. Deland and first introduced by Harvard in a collegiate game against Yale in 1892. Despite its effectiveness, it was outlawed two seasons later in 1894 through the efforts of the rule committee led by Parke H. Davis, because of its contribution to serious injury. After his playing career at Yale ended in 1882, Camp was employed by the New Haven Clock Company until his death in 1925. Though no longer a player, he remained a fixture at annual rules meetings for most of his life, and he personally selected an annual All-American team every