Twenty-two years into the slowest piece of music in the world, a significant musical development has taken place – a slight chord change. The 639-year organ piece by experimental composer and philosopher John Cage has added a single tone to the chord in the church where it is being continuously played in the German town of Halberstadt. The six-note chord, played in the Burchardi Church since February 2022, has now evolved into a seven-note one with the addition of a pipe playing a D note set to sound continuously for another four and a half years (until August 2028). A specially built and auto…