Modern pop/rock owes a great debt to the blues. This “tonal system” includes not only songs that are explicitly based on a 12- or 16-bar blues progression, but also songs that exhibit harmonic structures that have grown out of those patterns—most notably the prominence of V–IV–I in recent rock.

For example, the eighth-chord cycle that forms the basis of The Beatles’ “Let It Be” ends I V IV I, and this “backwards” classical move is the main harmonic punctuation at end points within the song.

For more blues-based rock examples, see the blues progression resource.