No signs, advertisements, billboards, solicitation, or advertising structures or materials of any kind shall be displayed or placed upon any lot; provided, however, a sign of reasonable size provided by a contractor for security services placed within 10 feet of any entrance to a lot, street numbers and name signs on lots and one sign containing not more than 4 square feet of surface area per side and used solely in connection with the marketing of the affected lot for sale or lease shall be permitted.