Country Knolls was laid out in gentle curves, and a mower has to know how to follow them. Saturday mornings in Clifton Park sound like this: a screen door, a sprinkler ticking somewhere, and Mr. Lawn Man moving up one side of a yard and down the other. There is real satisfaction in the last pass — the trimmer line snapped tight around the mailbox post, the clippings blown off the walk, the whole property suddenly looking like somebody loves it. That, more than anything, is the point of the job. Mr. Lawn Man mows, trims and tidies yards across Clifton Park, Elnora, Round Lake and the streets over into Halfmoon.