On a corner lot in any zoning district, nothing, with the exception of traffic signs, utility poles and open chain link or wire fences, shall be erected, placed, planted or allowed to grow between a height of 2 1/2 feet and ten feet above the centerline grades of the intersecting streets in the triangular area bounded on two sides by the street right-of-way lines and on the third side by a straight line drawn between two points on the street right-of-way line located 25 feet from the point of the intersection of the street right-of-way lines.