Plot: Broadcast of Prom 70: Missy Mazzoli, Bartók and Dvořák Bartok's sparkling Second Piano Concerto and Dvorak's Eighth Symphony are in the spotlight as American pianist Jeremy Denk joins conductor Karina Canellakis and the BBC Symphony Orchestra. The concert opens with Sinfonia (for Orbiting Spheres) by young American composer Missy Mazzoli, music 'in the shape of the solar system'