Lighting, if necessary, shall be limited to external, noncolored light, directed to minimize glare upon nearby properties and roads. Strings of lights are prohibited, except from November 1 to January 30, whether or not they are part of any sign. No sign shall contain flashing, intermittent, rotating or moving lights, nor consist of other moving, fluttering or revolving devices such as pennants, banners, ribbons or streamers; however, pennants, banners, ribbons or streamers may be employed on an occasional, temporary basis, not more than three times per year, for periods of one week, to call attention to special business or related events such as "grand openings," "special sales," etc.