The universal machine is a musical about Alan Turing, the mathematician and WWII code breaker who was convicted of homosexuality in the 1950s, chemically castrated as a result, and died young in mysterious circumstances. How do you turn such a story, and the maths in it, into a musical? We talked to writer and director David Byrne, Richard Delaney, who plays Turing, and Assistant Director Natalie York.