"Subdivisions" was one of the first songs Rush had arranged for "Signals". After Peart devised a set of lyrics, Lifeson and Lee wrote a collection of musical ideas to fit Peart's words. Peart recalled that his bandmates interrupted him as he was cleaning his car and set up a portable cassette player on the driveway outside the studio, and played him what they had come up with. Peart added: "I listened closely, picking up the variations on 7/8 and 3/4, the way the guitar adopts the role of rhythm section while the keyboards take the melody, returning to bass with guitar leading in the chorus, then the Mini-moog taking over again for the instrumental bridge", and told Lifeson and Lee that he liked it.