I think Duke Ellington had already started years ago. For example, he took one - he was famous for taking one tune and making it - Harry Carney played the melody. Then a year later, he'd write another arrangement, the same tune, but don't have Harry Carney. Just have Ray Nance do it. Same tune. In other words, he's able to get more mileage out of one tune than anybody I ever knew. So what he did with Come Sunday, for example, with the beautiful ballad. He used that for David Danced for Bunny Briggs, where the rhythm section's playing double-time [Bellson sings this melody while tapping a double-time tempo as accompaniment]. That was an example of what he did with - he wrote that a long time ago. He'd been gathering material off and on for a long time. He finally put the pieces together and made his sacred music.