Section 1015.2.2, All retaining walls thirty (30) inches or higher shall be provided with guard rails in accordance with this Section. Section 1015.4.1, Ladder Effect. Guards shall not have an ornamental pattern that would provide a ladder effect for any of the following uses: Assembly (A), Education (E), Mercantile (M) Residential (R) or any other uses open to the public. Exceptions: Section (b) above shall not apply where A, E, M, and R are accessory uses only.