Nate Wooley explains the set-up of his Battle Pieces as a ‘social form’ which, in practice, works out as a network of nested together structures, one designated soloist improvising on the parameters of a piece as the other members of the group weave around a loose-leaf book of shorter and longer compositions; then the spotlight shifts to a different soloist. Compositional forms are digested inside improvisations that could not exist without the very thing they are devouring. If this all sounds academic and contrived, fear not. The music is quick-witted and elegantly expressive. Wooley opens with fast, yet soft sounds, mute in place, like he’s summoning up the spirit of Rex Stewart or Cootie Williams; Laubrock has plenty of scope to unravel her trademark digressive lines; Courvoisier and Moran paint with rich harmonic palettes. There’s no bass, no drums, which helps keep these instrumental textures fluid and restlessly on the move, dividing and re-grouping, clustering together then fragmenting, like blood cells.