On any corner lot in a residential or agricultural district, no fence, wall, hedge, or other planting shall be allowed to obstruct vision between a height of two and one-half feet and 10 feet above the centerline grades of the intersecting streets. Nor shall the above be erected, placed, or maintained within the triangular area formed by the right-of-way lines at such corner and a straight line joining the right-of-way lines at points which are 25 feet distant from the intersection of the right-of-way lines, and measured along the right-of-way line.