“II started thinking of myself as someone who created things that would carry on having their own life,” Brian Eno says early on in the Eno documentary that I watched. Although who knows what he’ll say when you watch it. He’s talking about his interest in generative music: music fed into systems designed to alter it on every play through. It’s a process, inspired by the increasing complexity of evolution, which Eno has been playing around with ever since his early experimental album ‘Discreet Music’ in 1975. “Instead of thinking ‘I’m going to make something’, you think ‘I’m going to plant something’,” he explains in a documentary constructed as just such an ever-evolving piece of art.

To explain: Eno is a generative film. Each time it’s screened or watched, it will be different. A software system constructs a new documentary from hundreds of pieces of footage with billions of possible variations; at key points in the film, you can even see it working in a burst of sound and code. Director Gary Hustwit can add extra scenes into the mix later on, allowing the film to keep growing and developing over years. At various points a guest star – I got artist Laurie Anderson – picks out one of Eno’s legendary Oblique Strategy cards, designed in the ’70s to add a sense of experiment and unpredictability to albums such as Bowie’s Berlin trilogy with commands such as “honour thy error as a hidden intention” or “try faking it!”. Whichever card they pick then influences the ongoing direction of the film. It really is, in cinematic terms, as Eno as you can go.

All of which, of course, makes reviewing the thing a bit like giving four stars to “the telly”. But judging by the loose chronology of the version I saw, it’s likely – as with much of Eno’s music – that a solid narrative structure underpins the randomness. After fixed opening scenes of Eno crafting sonic worlds in a bright garden-side annex of his home, looking as though he’s making ambient dance breakfast, we take zig-zags through his career in a vaguely sensible direction of travel. The main beats of his story – his childhood love of US R’n’B, his glam-era Roxy Music days, his ambient awakenings, his helming of seminal albums by Bowie, U2 and Talking Heads – are hit between regular detours into his themes, mindsets and philosophies: nature, art, ecology, the creative process or the workings of a frog’s eye.