In 1947, a 25-year-old undocumented immigrant stepped off a train in Paris with half his face scarred, his left eye missing, and a death sentence waiting in Greece. This episode explores how Iannis Xenakis, born in 1922 in Brăila, Romania, to a wealthy Greek family, lost his pianist mother to measles at age five, absorbed Mozart, Homer, folk chant and physics at boarding school on Spetses, and then joined the Greek resistance during the Axis occupation. Fighting British tanks in the streets of Athens in December 1944, he was struck by shrapnel from a tank shell that shattered his cheek and palate, yet he survived to finish his civil engineering degree before fleeing on a fake passport.

The conversation follows his years as an engineer in Le Corbusier’s studio, where he designed the hyperbolic-paraboloid Philips Pavilion for the 1958 Brussels World’s Fair, and his nighttime struggle to become a composer despite rejection by Arthur Honegger over parallel fifths. It was Olivier Messiaen who told him to stop imitating others and translate his architecture and mathematics directly into sound, producing Metastasis in 1953 with 61 independent orchestral parts drawn from architectural curves on graph paper. The episode covers his use of game theory, the statistical mechanics of gases and Brownian motion, his UPIC drawing-tablet computer system, his Polar Music Prize, and his death in 2001.

• Why survivor’s guilt drove Xenakis to feel he owed the dead something monumental
• How the same curves used for the Philips Pavilion became sliding string glissandi
• Why music built on the mathematics of gases sounds like a thunderstorm rather than a calculator
• The UPIC system that let him draw shapes with an electromagnetic pen and hear them instantly
• What a staunch atheist’s raging string sections reveal about art in the age of algorithms