This is a tool to help any musician compose chord sequences. W.A. Mathieu created this "harmonic map" based on manipulating the overtones of the central chord C.Start in the middle with C major, and follow the map along any line or dotted line to find the next chord in your composition. Almost any direction you take sounds good, or at least plausible. Have fun with the new harmonic motion. For more info read Harmonic Experience by W.A. Mathieu.