No person shall operate a motor vehicle, upon which license plates are required by law to be displayed, unless the license plates legally registered and issued for such vehicle shall be fastened in such a manner, and not covered, obscured, or concealed by any part or accessory of such vehicle or by any foreign substance or material, to be readable in its entirety from left to right.
(`63 Code, § 335.10) Penalty, see § 71.99