Barbara is a physician and pianist. Margo is a brilliant mathematician and cellist. Lucia is a philosopher, nun, and violinist. These amateur but talented and accomplished musicians have met to celebrate the silver jubilee of their Vows. This year the plan was to play, in its entirety, the music that brought them together and made them sisters in heart and mind for life: Tchaikovsky's Trio in A minor for Violin, Cello, and Piano; and they played...