Setup box play
2 starts the play by cutting
3 is pushed out by 2, and continues for a deep cut, and 4 fills as the swing
Play continues, if 4 needs to cut, they take the in-field cut. 3 can begin to cut in, and 2 can strike in the end zone.
Let's reset to show another initiation from the Alpha box play.
2 cuts straight up the field. 3 and 4 need to react.
3 cuts in to become the fill on the swing, and is an option on the in-cut. 4 cuts deep as they've been pushed out by 2.
From the last step 4 cuts in, 3 finishes the cut as swing, and 2 can start to move to strike in the end zone. Basically, the formation becomes a box once more.