From the article:

At its core, the drawing is the circle of fifths, familiar to most musicians. Coltrane's version fills in the circle with chromatic scales, separated into two circles of whole steps, that join the fifths. Lines then trace different harmonic relationships between the notes, uncovering shapes that reveal the chord structures behind "Giant Steps", arguably Coltrane's most famous harmonic experiment.

In this post, we'll rebuild the diagram as an interactive widget and attempt to decode its harmonic secrets.