#1 and #2 skip the ball to each other
x1 and x2 move on the flight of the ball, closing out to their man and sprinting to the helpline
After several passes, the next player in line subs in on the fly with the defensive player on his side of the court and verbalizes the switch
This action repeats throughout the duration of the drill
Jump to the ball
Move on the air-time of ball - be there on the catch
Maintain proper gap and help positioning off the ball
Practice proper closeout technique
Modification: You can add the dribble to also work on ball control and gap protection on drives