This Greek composer and sometime architect often favoured mathematical structures in his music, but it would be a mistake to think of his works as being imprisoned by any kind of grid. When the keening glissandos that crop up in many of his compositions bump against the spiky, extended-technique textures that Xenakis instructed musicians to employ, the results are anything but predictable. That those wild swings of mood tend to cohere into persuasive overall works is a testament to his skill, whether he was writing for string quartets, electronic music or orchestras.