The immortal quote from Alvin Curran’s New York Times blog today:
Elliott Carter told us the first day of composition class, “You can bring anything in here you want, except octaves.”
Alvin continues: “Octaves are in essence sandwiches with nothing inside, and I love them.” (I seem to recall that Carter’s Piano Sonata, one of the best pieces he ever wrote, starts with a multiple-octave B.)