- Each of the intervals (roman numerals) is a chord in a key such as "III" in the key of C would be an E minor chord.
- You can start on any of the intervals and create a progression.
- Every line that connects one interval to another means you can go either way meaning you can go from a V chord to a II chord and then back to a V chord.
The red lines are ones that connect chords that share one similar note, the black lines connect chords that share two notes. This can be seen here in the following diagram.
- This diagram shows the connections between chords in the key of C
- The top set of notes in each box is the chord that the rest below it in the box are being compared to
with I being C-E-G (C Major)
I hope you enjoyed this version of how chord progressions work and I hope it can help someone understand it better.