Harmonics # 2-3-4-5-6, back rounded vowels

This video refers to this image here on OMN:
With an aspiration to become the Betty Dodson of the vocal folds, an exercise with the back rounded vowels, which may bring out the first elements of the harmonic series.
This is not 'overtone athletics', I aim to use 'neutral', not constrained voice quality with a focus on carefully shaping the vocal tract and the lips... and listening!

It is the merging of phonetics, music and mathematics in one natural primordial and holistic language.

Proportion/ Interval/ approximate vowel sound (please do not interprete the correlation too rigidly!):
2:3/ just fifth/ [u]
3:4/ just fourth/ [o]
4:5/ just major third/ [ɔ]
5:6/ just minor third/ [ɑ]

To separate the vowel sounds I use the [ŋ] nasal which also helps accentuating the overtones.

NB! It will probably be beneficial to begin the exercise with only two neighbouring elements.

4:5:6, - the major triad - is a signpost which is really worth listening for and practising the accentuation of to find orientation in the harmonic universe.