What are the formation, motion and snap rules?

• The offense must have at least one player (the center) and up to four players on the line of scrimmage. The quarterback must be off the line.
• The center snaps with a rapid, continuous motion between the legs to a player in the backfield, and the ball must fully leave the center's hands.
• Only one player may be in motion at the snap. That player must be off the line, and the motion must be parallel to or away from the line of scrimmage.
• Players may shift at any time, but everyone must reset for 1 second before the snap.
• Movement by a set player that simulates the snap is a false start.
• No player on either side may enter the neutral zone before the snap; it's an automatic dead-ball foul (officials may give a courtesy warning first).

Penalties: illegal motion (more than one player moving) and false start are each 5 yards and loss of down.