"Back-to-back sign structure" means a sign structure configuration where two advertising faces or sign areas are parallel to one another and face in opposite directions, and such that the backs of the advertising or sign area (back view) face each other and are not more than three feet apart. (Added by Ord. 13-073, Dec. 11, 2013, Eff date Dec. 26, 2013; Amended by Ord. 13-074, Dec. 11, 2013, Eff date Dec. 26, 2013).