LW starts with the ball and passes it to LB.
From here the ball is passed to CB, who now crosses with LB.
After the cross CB runs to LB's position.

LB now has 2 passing solutions:

1 -	Pass to RW and then take CB's position. RW can pass to RB and the exercise can be reversed.
2 -	Pass to RB and then take CB's position. RB passes to RW, who returns the ball to RB and the exercise is reversed.