B passes the ball to the playmaker, who then plays a high ball into the backfield.
B defends this ball back to the playmaker, who then gives a setup for B.
B attacks this setup.
After the attack, A takes B's place and B becomes a reserve. The playmaker stays.
The attackers use the left half of the court with one playmaker. The middle attackers and diagonal attackers use the right half with another playmaker.
Extension:
After the service, A takes a second ball.
After B's attack A throws this ball into the field.
B plays this ball to the playmaker, the playmaker gives a setup.