There is more green in this borough than anyone gives it credit for, and the Unisphere stands in the middle of the largest piece of it. The Greencity company works the smaller pieces — the front lawns of Corona and Elmhurst, the strips beside two-family houses, the backyards you reach through a gate along the driveway. In May the mowing begins in earnest, with edging, hedge trimming, mulching and the cleanup that clears a winter's worth of paper and grit out of the shrubs. Small yards reward precision, because every square foot is visible from the sidewalk. Done right, a twelve-foot lawn on a dense block reads like an open window.