The Upper and Middle forms of the Minor 11th / Symmetrically Extended Major 7th arpeggio tell an interesting story of the symmetry of the diatonic system on the guitar fretboard in standard tuning.
As the Fretography® method is all about symmetry, the diagrams below lay out that symmetry on two levels. Look for the tonic (Roman numeral I) and where it appears in each form. Also notice the fret axis positions indicated by grey bars.
The Axis frets are rooted in II (Dorian Axis), III (Phrygian Axis), and VI (Aeolian Axis).
The yellow curve connects the II positions within the four upper strings.
The boldly outlined reversed "Z" shapes comprise the primary arpeggio forms. The extensions are shown behind with shaded edges. Notice that the upper forms differ only in the position of a single note position in each (VII and IV).
The Middle Form of the arpeggio is centered on a different fulcrum with the Dorian Axis at its outer edges. As with the upper form, the overall skewed symmetry of this form differs by only the positions of the IV and the VII in the extensions.
Again, consider that these arpeggio forms are based on the only instance of a six note interval sequence which occurs twice in every key. There is literally no arpeggio on the fretboard which
contains such clear symmetry over such a wide range both tonally and geometrically.
Next time we'll look at the lower form.
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