Section 15. Billboards

No signs, advertisements, billboards, or advertising of the lots hereby restricted without the consent in writing of Shannon Valley Developments; provided, however, that permission is hereby granted for the erection and maintenance of not more than one advertising board on each lot or tract as sold and conveyed, which advertising board shall not be more than 5 square feet in size and may be used for the sole and exclusive purpose of advertising for sale or lease the lot or tract upon which it is erected.