That’s been Greenwood’s role ever since — he’s the guy who can take an abstract Thom Yorke notion and master the tools required to execute it in the real world. The most recent Radiohead album, “King of Limbs,” sounds as if it has less Greenwood on it than ever, until you learn that a lot of the music was pieced together using a bit of sound-looping software that Greenwood programmed. Post-“Kid A,” Greenwood says, Radiohead has evolved into a band of arrangers. They start with an idea — usually some chords, a melody and some kind of a speed — and figure out how to orchestrate it. Recording a song by playing it together in a room has become just one of several options they can pursue while recording: a setting on the machine that is Radiohead.

“Jonny likes having the ground pulled out from under him, musically,” Yorke says. “More than any of us. Which is a constant source of relief to me, because I’m the same way, but I don’t know how to get there, usually.”

“I think, were a stranger to come and watch us,” Greenwood says, “he’d be surprised how — not exactly amateur we are, but how uncertain, the whole time. There’s never that certainty, at the start of each song or project or piece of music, that it’s going to work. And that hasn’t changed.