[Ref in PA]

Lane spaces are set up to be 3 feet by 3 feet. The defense must occupy the two bottom spaces (unless the lane is cleared for any reason). The next two spaces MAY be occupied by teammates of the player shooting the free throw. No more than two teammates of the shooter may be on the line. If any of the teammates of the shooter choose not to be on the line, that spot MAY be fill by a defensive player. The defense is limited to a minimum of 2 and a maximum of 4 players along the lane while the offense has a minimum of 0 and a maximum of 2 along the lane.

Review rule 8-1 (all articles), 9-1 (all articles), 1-5-2.