Common Ground employs three different repetitive techniques. The first third of the piece is a cycle of chords of expanding and contracting length, with the violin and cello trading agitated little lines. The second is a pastoral obsession over essentially one chord: light changing over a field. Here, the cello leads, and the violin and piano offer insect-like interruptions. After a metronomic interlude and a free-form interlude, the piano begins stating a ground bass – a repetitive line around which the harmonies constantly shift. This sort of thing pops up in Purcell, where I first encountered it as a choirboy. The piece ends with a hyperactive recapitulation and is approximately 9 minutes long.