The rest of the second side contains "Supper's Ready", a 23-minute track formed of seven parts and the longest the band recorded. Gabriel believed the band's growing support as a live act gave them the confidence to start writing extended pieces. The song and its theme of good versus evil was inspired by an experience Gabriel and his then-wife Jill had with Anthony at Kensington Palace, when she reportedly entered a trance state as the room's windows suddenly blew open. Gabriel compared the ordeal to a scene from "a Hammer Horror film". Initially, the song took form as an acoustic track similar to "Stagnation" from "Trespass" or "The Musical Box" from "Nursery Cryme", something the band wished to avoid repeating. To develop the piece further, Gabriel pitched his idea for what became the song's fifth section, titled "Willow Farm", on the piano. Banks noted the change from the song's more romantic introduction into "Willow Farm", with its "ugly chord sequence", worked as it took the song "into another dimension". Genesis went to the street and picked eight children to record vocals for the song and paid them ten 'bob' (shillings) each. "Apocalypse in 9/8" was improvised by Banks, Rutherford and Collins. It is a mostly instrumental performed in a 9/8 time signature that began with Rutherford playing his bass pedals which Collins recalled as "totally abstract with no time signature" and incorporated a drum pattern to it. Banks assumed his organ solo would have no vocals, but after Gabriel proceeded to record lyrics over it, something that he disagreed with initially, he said, "it only took about ten seconds to think 'This sounds fantastic, it's so strong. Banks picked "Apocalypse in 9/8" and "As Sure as Eggs Is Eggs" as "the best piece of composition" Genesis recorded during Gabriel's tenure as lead singer, but thought Gabriel had written the lyrics too quickly. Collins supported this view, who recalled Gabriel rushing to get them written while the backing tracks were being recorded.