Carreaux, which is French for "squares", "checks" or "diamonds" (the lozenge shape and the suit in cards), is based not only on the idea of squares of all kinds, but also more complex relationships between them - mathematical, philosophical and mystical. The antiphonal element of the piece is an integral part of its structure: the four trombonists stand several metres apart, forming a diamond or square around and amongst the audience, so that the music moves in both time and space.

The title also gives a nod of homage to Stockhausen's Carré (and there are many cryptic allusions in the piece to other important influences, from Wagner through Stravinsky to Xenakis). Carreaux is in eight sections.