Hofstadter, Douglas. Gödel, Escher, Bach: an Eternal Golden Braid. Basic Books, 1979.
Six-voice ricercar from J. S. Bach’s Musical Offering, BWV 1079
Q: What do the shapes signify?
A: The ovals (eggs, ellipses) are the theme; the rhombi (diamonds) are everything else.
Q: What is a ricercar?
Q: Is this the most significant piano work of the last millennium?
A: At least one person thinks so: http://tinyurl.com/RosenOnBachsSixVoi…
Q: What instrument is that?
A: It’s two instruments, actually: a harpsichord and an organ. The harpsichord is Atema’s “Pristine Harpsichord” (with all stops on); the organ is two Ahlborn-Galanti Archiv modules, using the following stops (in order from the top voice):
Cor Anglais 8′
Flauto Mirabilis 8′
Prinzipal 8′ + Gedackt 8′
Ophicleide 16′ (up an octave so that it’s at pitch)
Q: Where can I get the sheet music for this?
A: Here is Bach’s autograph …
… and here is a modern version …