Here is how it gets back to C from the G# .................................................... (6) ... A# D# 7/8 ~8/3~ 7/3 G# D# 49/64 ~64/21~ 7/3 (wolf fifth 64/21 = 729.2 cents) (7) E A C# E 49/81 ~4/3~ 196/243 ~12/7, 9/7~ 28/27 ~4/1, 3/1, 7/3~ 196/81 (A major chord with 9/7 for the third) E A C E 49/81 ~4/3~ 196/243 ~81/49, 243/196~ 1/1 ~4/1, 3/1, 196/81~ 196/81 (A major really - shown on score as minor - with 243/196 = 372.1 cents for the third) (8) E G C A# 49/81 ~243/196~ 3/4 ~81/49, 4/3~ 1/1 ~144/49, 64/27, 16/9~ 16/9 (C minor dom7th with 98/81 as the third - shown as C major dom7th on the score but the E is carrying through from the C# root control earlier, so is still tuned to 49/81, which is closer to Eb than E) C E G (+ two higher Cs at octaves) 1/2 ~98/81~ 49/81 ~3/2, 243/196~ 3/4 (C minor, 98/81 = 329.832 cents as the third) (1) 3/4 ~5/3~ 5/4 ~8/3, 8/5~ 2/1 (C major) .................................................... The way it gets back to C major from the Ab is a very fast transition: (root control Bb) Db Eb Gb Ab Bb (root control C) Bb E G C E G This is a much more straightforward return, with all the chords pure except the 21/16 in the septimal pentatonic, and ends the piece: (11) ... (the septimal pentatonic Db Eb Gb Ab Bb, with all those intervals shown in the SCALA listing (12) Bb E G 7/16 ~20/7~ 5/4 ~24/7, 6/5~ 3/2 C E G 1/2 ~5/2~ 5/4 ~3/1, 6/5~ 3/2 You've got the Bb carrying through to tie the chords together to ensure that the Bb is a 7/4 if using the 7-limit scale. (though it is two octaves below the one in the previous chord)