It shall not be lawful for any person to erect or set up any portico, steps, or any other ornamental structure whatever, on Mount Vernon Place, a greater distance into the place than 9 feet, measuring from the building line thereof. City Code, 1879, art. 45, §43 1893, art. 46, §21 1927, art. 29, §27 1950, art. 30, §5 1966, art. 21, §6 1976/83, art. 21, §5 Rev. Ords. 1858-059