The Beatles’ song A Day in the Life from the Sgt. Pepper’s Lonely Hearts Club Band album (1967) is a sound engineer’s nightmare (or dream!). Fundamentally, it’s a patchwork of two unfinished tracks linked by an orchestral transition involving some 40 musicians. It ends with a track played in reverse and a 15-kilohertz tone that only dogs can hear! According to legend, it was Paul McCartney’s idea, as he wanted to pay tribute to his Shetland sheepdog.