An examination of that timeless truism: necessity is the Frank Zappa & the Mothers of Invention (exact phrasing still under review). Our three categories are about what happens when musicians impose limitations on their creative processes, and how that can enrich their modes of expression: (1) songs that use only one chord; (2) melodies that use only one note; (3) songs that use only one instrument. Featuring music from Harry Nilsson, The Killers, Dean Martin, and more.