“We started with a good guitar sound, but it wasn’t what exactly we wanted to hear. So we sat down with a Bell flanger, and we basically put the whole track through it. It gave everything a lot of movement.

“The song wasn’t rehearsed; it was constructed in the studio from various pieces. I had the Wurm part from another band I used to be in called Bodast. It was in a song called The Ghost Of Nether Street. We’d recorded an album, but the label closed down, and so the record never came out.

“I always loved the section as a whole piece of music, so I decided to carry it over to Yes. I like the way it goes from G to E-flat to C, but different things happen on the roots. Although it repeats endlessly, it sometimes has the fifth below roots on the chords. It sounds like a lot going on, and of course, it’s flanged.

“The build-up of it is very impressive. It splits into two guitar tracks, one side taking a solo. Somehow, we did a bunch of takes, and so we’d pick the best of each. They were all done as complete takes. I remember thinking that I was sort of jamming with myself.

“The rest of the song is wonderful too. Jon had some fantastic writing on it. It’s arranged nicely. We did very little overdubbing, really.”