Sailplanes go up off Harris Hill on warm afternoons and turn over the valley without making a sound. Down below, the mowers are the only engines running. Mayo's Landscaping takes the hillside yards and the flat ones both, cutting grass, running the trimmer along fence lines and stone walls, edging drives, and carting away the clippings and brush a season piles up. Late-day light comes in sideways over the ridge and shows every stripe on a fresh-cut lawn, which is the hour to judge whether the job was done right. It usually was.