Jake Voytko examines the overlap between software and songs in Music and Design Patterns.

Chord changes aren’t represented in the core notation/language of the music, but you can use musical notation to spell out changes. You can also use shorthand languages to design the music. The sentence “12-bar in Bb, 2-5-1 turnaround, on my lead” gives away none of the implementation details (voicings/melodies, etc.,) yet the song is written in a breath.

Design patterns act the exact same way for programmers. They are, at heart, a common framework by which programmers can discuss a design. They can spend less time focusing on minutiae and more time discussing design and code.