Originally Posted by ribbons

"And of course Henry the Horse dances the waltz!" I believe the waltz-middle of the song consisted of Lennon and George Martin playing different organ patterns recorded at half-speed, further condensed by overlaying more organs, harmonicas of different sizes, and harmoniums to create the carnival atmosphere. George Martin and Geoff Emerick (engineer) created an effects tape with snippets of real calliopes and steam organs playing various songs, with each snippet later distorted so that the original songs were unrecognizable. This culminated in an ingenious (for the time) aural recreation of “Pablo Fanque’s Circus Royal".