Each building and complex of buildings shall have an architectural scheme with appropriate variations in design to provide attractiveness to the development; compatible within the development and in relationship to adjacent land uses. Such variations in design shall result from the use of landscaping and the orientation of buildings to the natural features of the site and to other buildings as well as orientation to the sun so that solar energy may be utilized and from varying unit widths, using different exterior materials; changing roof lines and roof designs, varying building heights and changing window types, shutters, doors, porches and exterior colors. Architectural elevations shall be submitted to the Board for review and approval. Dwelling unit designs may be varied by differences in unit width and setback.