The following building materials shall be allowed in the construction of the exterior walls of buildings and structures constructed and installed in an OP-1 Office Park-1 Zoned District in the City:

    A.    The exterior walls of a building or structure that is visible from a public right-of-way shall be constructed of one (1) or more of the following:  (a)  brick;  (b)  brick veneer;  (c)  natural stone;  (d)  marble;  (e)  granite;  (f)  glass.  The design materials shall be used in such a way as to blend with the scale, color, and traditional architectural character of the district.

    B.    The exterior walls of a building or structure that is not visible from a public right-of-way shall be constructed of any of the materials listed in the preceding paragraph "A" of this Section 17.58.050 of this Zoning Code.