Dimension of the playing area is about 20-25 x 20-25 meters square.
Two teams play against each other. Both teams are split into two groups of four. One group (4 players) is located in the middle and the other one (4 players) is on the edge of the playing are as shown.
So, 4v4 game is played inside with the help of the wall players.
Both groups outside have a ball and they perform two tasks at the same time. As wall players, they help their team-mates to keep the possession inside, besides they have to circulate their ball without missing or losing it outside.

Teams change their positions and roles after every repetitions.

Load: 60 sec.

Rest: 30 sec.

Sets: 4-8

One team starts the possession inside. They try to keep the ball with the help of their team-mates outside.
After losing possession the roles are changed automatically and the game continues without interruption. 
The defending team tries to win the ball back as soon as it possible.
The players outside have double tasks. They have to help the possession acting as wall players on the edge of the area , besides they have to circulate their ball without losing or stopping it, avoiding collisions with another ball or player.