How did Miley Cyrus' "We Can't Stop" become a '50s-style doo wop number? Since when was Meghan Trainor's "All About That Bass" about an upright bass fiddle? At what point did Macklemore's "Thrift Shop" evolve into a '20s hot jazz tune? And whose idea was it to rework Lorde's "Royals" into a polished ballad sung by a sad clown? It's all part of the topsy-turvy world of Postmodern Jukebox, an ongoing musical project spearheaded by pianist and arranger Scott Bradlee, who takes contemporary pop and rock tunes and fashions new arrangements for them that cast them in an unpredictable variety of musical styles from the past.