Two players in Motion

[bigjohn]

Is that why signal 20 is one arm moving for illegal motion and two arms for illegal shift?

Doesnt Rule 7-2-2 say:

ART. 7 . . . Only one A player may be in motion at the snap and then only if
such motion is not toward his opponent’s goal line. Except for the player “under
the snapper,” as outlined in Article 3, the player in motion shall be at least 5 yards
behind his line of scrimmage at the snap if he started from any position not clearly
behind the line and did not establish himself as a back by stopping for at least
one full second while no part of his body is breaking the vertical plane through
the waistline of his nearest teammate who is on the line of scrimmage.

illegal motion (Art. 7) – (S20)