"out to 60 semitones" -- does this mean you're interpreting the diagram as a pitch-map covering five octaves? I was interpreting it as a tone-map comprising 12 semitones grouped into five distinct tonal regions with the center web indicating specific movements from one tonal region to another.
EDIT: Just saw your other comment interpreting it as a spiral, which effectively answers my question.
I think the importance of there being five tonal regions is that this enables the multiples of 12 to line up at 60. These numbers are significant because they connect back to the Babylonian sexagesimal ("base 60") system used in both music theory and trigonometry.
