A touchdown may be awarded by the referee in the NFL as a punishment for a "palpably unjust act," such as a player coming off the bench during a play and tackling the runner who would have scored otherwise. The rule is found in Article 78 of the rules, which states: "A touchdown can be scored by the opposition [= team that does not possess the ball] if a foul by a player or member of the coaching staff reduces the number of players on the field below the required minimum for either team." This rule was adopted in response to a situation where a player came off the bench in the final minute of play and ran down a loose ball carrier who had just gained several yards on a punt return. In addition, since the 1970s, when National Football League (NFL) teams began substituting players at will during games, some opponents have been able to score touchdowns this way by using various formations on special plays called "drives". For example, one drive might include five players lined up at the line of scrimmage with two tight ends off the side and one running back behind the center, while another drive could feature four wide receivers and one running back, with each player performing a different function on the play.