In the documentary, "Gene Deitch: The Picture Book Animated", director Gene Deitch says that tuned pieces of wood were used to create the music. In addition to a xylophone and a marimba, there were a lot of wooden instruments from Frantisek Belfín And His All Wooden Orchestra. A wooden crate was used as a bass drum. One instrument was invented for "Changes, Changes". Deitch called it the "plankoplonker" which he described as "a rank of ordinary 2x4 planks sawed to calculated lengths hung and struck with a wooden mallet" giving the bass tones to the music.