It will be four years later. You will be walking down a tree-lined street after a day of classes, dappled sunlight shining softly through a layer of swaying branches, all lilting and turning and twisting in the breeze. There’s a good chance you will be deeply content, breathing in a lungful of fall air that has just begun to turn. You may cross paths with a smiling stranger on the sidewalk, nod at her, and as she passes, catch the end trail of her perfume. The same warm perfume that the really cute girl in your sophomore-year science class always wore.