"I’ve got some real gone tricks in that tune," Duffy said, still playing. "Notice the beat after ‘one’? That’s a semicadence. Then you get another beat after ‘begun.’ That turns the end of the song into a semi-cadence, too, so you can’t ever end it. The beat keeps you running in circles, like: Tension, apprehension, and dissension have begun. RIFF. Tension, apprehension, and dissension have begun. RIFF. Tension, appre—"