This exercise is from Improving Your Team's Speed of Play
The players enter the box through one gate, make a pass through another and then sprint to the outside of the circle via a third. This throws up a number of problems to the dribblers regarding the availability of players on the outside.
What will also become apparent is that because players now don’t follow their pass out of the square to replace the player they pass to, gaps can appear on the outside of the circle. These obviously need to be filled and it can only be done by the movement of players on the perimeter.