Before the advent of the shot clock in basketball, four corners was a method of slowing down the game. It was popularized by Dean Smith at the University of North Carolina

Basically, when the Tarheels got a large enough lead, Coach Smith would spead the offense out on the court and pass back and forth to the players situated in each of the corners. No rule existed at the time that required a team to take a shot. This allowed the team in the lead to basically sit on the ball and wait to get fouled and to run as much time off the clock as possible. From some vague recollections, I can remember this going for periods of up to five or six minutes. Obviously this was not a fan favorite and rules introducing the shot clock were put in place, marking the end of the four corners style of play.