in any direction behind the line of scrimmage prior to the snap. Offensive linemen – Three linemen must be in a three- or four-point stance prior to the snap. They must line up guard, center, guard and next to one another. Any offensive lineman not covered up by the fourth man on the line of scrimmage is an eligible receiver if he is wearing an eligible receiver number (1-49, 80-89). Defensive linemen – The three defensive linemen must line up on the nose, or can line up inside foot-to-outside foot outside of an offensive lineman. Linemen must rush inside if nose up or slanted into if shaded, and they must make contact before any movement to the outside is made. Blitzing – Only one nonlineman can blitz at a time. This player can blitz from any direction, but must be at least five yards off the line of scrimmage/goal line prior to the snap. Players do not have to announce their eligibility to blitz. Defensive backs are not allowed to blitz. Linebackers – At least two defensive players must line up at least 5 yards behind the line of scrimmage. The other two nonlinemen must either line up face-to-face with an offensive nonlineman on the line, or be 5 yards behind the line of scrimmage. After the snap, this rule is eliminated and the players can roam anywhere they wish, provided it does not violate blitzing rules. Linebackers can line up at the goal line if the offense is within five yards of scoring. Kickoffs – If a kickoff leaves the field of play on the fly, the ball comes out to the 25-yard line. The sideline walls and end zone walls are not out of bounds, and balls can be played off of them. If a kickoff leaves the field of play after making contact with the field or a player on either team, the ball comes out to the 5-yard line, or the point in which it leaves the field of play, whichever is closest to the kicking team's goal line. Offense – No punting is allowed. The offense must attempt to gain a first down or touchdown, or may attempt a field goal (by placement or drop kick). Coaches – Starting in 2013, coaches were permitted to coach on the field again, which improved communication between their players and them. Overtime – Overtime is played with NCAA-style