21.51Same melody, three reharmonization levels

Suppose a simple phrase fits:

C | Am | Dm | G7 | C

Level 1 — color only

Cmaj7 | Am7 | Dm7 | G13 | Cmaj9

Level 2 — functional enrichment

Cmaj7 | E7 Am7 | A7 Dm7 | G13 | Cmaj9

Level 3 — chromatic

Cmaj7 | E7 Am7 | A7 Dm7 | F♯°7 G13 | Fm6 Cmaj9

Each level adds complexity.

Don't start at Level 3 automatically.