The variance is necessary because of special circumstances relating to the size, shape, topography, location, or surroundings of the subject property, to provide it with use rights and privileges permitted to other properties in the vicinity and in the zone in which the subject property is located. An example of such circumstances may be that a lot was established in a subdivision of which a portion may be unbuildable because of steep slopes; or, an adjacent property has a nonconforming side yard setback, in which case a fence taller than the allowable height or a setback on another portion of the property may need to be varied to allow the applicant the privacy or buildable space commensurate to that enjoyed by other lot owners in the district.