In Part 3 we saw that in just intonation there are four candidates for the tritone. They are simple fractions close to the square root of 2. We saw that they lie at the corners of a parallelogram in a diagram called the tone network, or Tonnetz:
This is a companion discussion topic for the original entry at https://johncarlosbaez.wordpress.com/2023/11/17/just-intonation-part-5/