Out on Beaver Street the glass of the old Lyman greenhouses fogs early in October, and the maples above the wall let go all at once. A Yard & A Half Landscaping Cooperative works the Waltham yards nearby — mowing and trimming through the growing months, mulch laid and bed edges held, then the long autumn sweep of leaves off lawn and walk. A cooperative shares the work and shares the standard, and it shows in how a property looks when the trailer gate goes back up. Nothing dramatic: grass at an even height, beds with a drawn line, a yard ready for whatever the sky does next. Waltham, with Weston, Lincoln and Watertown alongside.