They have a saying in Paris that describes the fast pace of life in that city: Métro, boulot, dodo, meaning that life consists only of an endless repetition of subway rides, work, and sleep. Life in Washington is harried, too, but sometimes you need to stop as you dash through the L’Enfant Plaza station at rush hour on a Friday in January. Who is playing the famous Chaconne from Bach’s D minor partita so well…