The second model concerns constituent parts being brought together by a writer or writers toward the envisioned end of a seamless whole. Classical pop songcraft of the type perfected by Hoagy Carmicahel or Cole Porter used this model as its compositional aesthetic. The rise of multi-track recording empowered producers to tinker with a song’s various elements, eventually making the producer a de-facto assistant composer; the Beatles circa Revolver are usually rightly cited as pioneers here, along with Brian Wilson, who saw that a recorded multi-track pop song ideally should resemble a floorplan for a two-story building more closely than a script for a one-act play.