Painters have chased the Rocky Neck light for as long as anyone in Gloucester can remember, and a well-kept lawn answers that light the way water does — flat, bright, holding the late afternoon. SIADesigns mows and tends yards on this harbor-cut peninsula, where a green square between shingled houses is a small and deliberate thing. Grass gets an even nap, the trimmer follows fence line and foundation, and clippings are never left to yellow the color out. By evening the shadows come long across it and the whole yard reads as one piece. The work carries from downtown out to East Gloucester and Annisquam.