She reaches behind her and turns on the radio, and the DJ, just coming out of commercial, welcomes her to settle in and listen to some Mozart, a boy genius who started composing at five. “The Piano Sonata Number Eleven,” the DJ says in a voice as smooth as toffee, “is also known as the Rondo Alla Turca. Composed as a trifle, it has, over time, become one of his most popular pieces the world over.”