There are 3 lines very close to one another in the middle of the pool at half tank. The line in the middle has the balls. On the first whistle man in the middle drives hard and fast to the goal with the ball. Approx. 2 seconds later the whistle blows again and the first people in each of the side lines become defenders chasing down the man with the ball. As skill level progresses, the time between the whistles should be shorter and shorter. The three lines can also be formed to the right or left of the goal so drives can come from an angle.