Highland Lake lies still enough on most East Andover mornings to hold the whole hill upside down in it. American Waterscapes tends the lawns that run down toward that shoreline — mowing on schedule, feeding the grass, cutting a clean edge where turf meets walkway and dock path. Summer in this part of Andover is short and generous, and a yard repays attention fast. Cleanups bracket the season at either end; the weeks between are simply a matter of showing up on schedule. Green, level, well kept, and looking like it belongs to the water it faces.