No fence or wall except a retaining wall, or a wall of a building permitted under this Zoning Ordinance, over six feet in height shall be erected within any of the open spaces required by this Zoning Ordinance unless that portion of the fence or wall which exceeds six feet in height has a ratio of open area to solid area of at least four to one.
(Ord. 81(66-67). Passed 12-15-66.)