Summer in Littleton runs on a long leash — the South Platte low and bright, the days stretching past nine, a mower going somewhere on every block until dusk. Littleton Student Enterprises works right through that stretch, cutting lawns, trimming fence lines, edging walks, bagging or blowing the clippings off clean. There is an old and pleasing feeling to a yard mowed by somebody working their way through a summer, and to the straight lines they leave behind them. Cleanups in spring and fall bracket the season on either end, clearing what the wind and the cottonwoods dropped. Between Dakota Ridge and Littleton, thaw to first snow keeps the schedule full.