There is an hour in June, once the heat lets go, when the light comes sideways through the trees and every mowed line stands up in relief. Summersweet Design keeps lawns in Rainbow Lakes, threading mower and trimmer between the stone walls, fern banks and rock outcrops the glaciers left behind up here. Nothing about these yards is rectangular, which is the fun of it — the cut has to follow the land, tucking around ledge and root and the shade line under the pines. Mowing, edging, trimming and the seasonal cleanups are the whole of the job, done at the pace the ground asks for. When that evening light finds a lawn just finished, you can see every pass.