It is unlawful for any commercial or industrial operation to display lights in such a manner so that the beams or the rays from the light source shall be directed to and unshielded from adjacent residential properties. All light sources used for advertising, security or safety purposes shall be arranged or shielded in such a manner so that they will not constitute a public nuisance for residential property owners. (Ord. 1324 § 1; prior code § 20.35.4 (A)).