When I went to school in Boston, I took the subway all the time. Out of the four years or so of almost daily train rides, I came away with a handful of indelible memories. One night on the way home from some event, I sat alone across the aisle from a young family — husband, wife, and two daughters. The older was probably about seven or eight years old, about the same age as Cecelia is here, and wouldn’t sit down as the train bucked and weaved up the line. She defiantly challenged the forces of the train to knock her down while her parents looked on in resigned frustration. And she never fell. Some twenty years later, I got to relive that little vignette with my own daughter.