Set up four squares as shown. Four players are in each area (2 blue-2white now) and 1, 2 or 3 link players are in the middle marked with different colored bibs.
There is one ball in each area.
Roles and positions of the players are changed periodically.

Duration: 30-90 sec.
Rest: 30-45 sec.

After determined combinations in the squares, the players have to decide that, how they deliver the ball to the other square. They can play the link-players or they can pass the ball directly to the other (determined) area according to the given situation. In the interest of the continuous implementation, it's important that the players perform the combinations and change the area at the same time. The directions must be determined and periodically changed.
This exercise contains two variations.
The first variation is simple, the second one is more complex.