The major 6th on the guitar
9 semitones · M6 · C → A
Its character, in the app's words: warmth; an octave wider (M13), generosity: the warmth expands.
The shapes on the neck
- On the same string: 9 frets up.
- On the next string, towards the 1st: 4 frets up; 5 frets up when you cross from the G string to the B string, which are tuned a major 3rd apart instead of a 4th.
- Turned upside down it becomes a minor 3rd: 9 + 3 = 12 semitones.
The root is the C on the A string, 3rd fret; the other circles are the same note, A, wherever it sits between frets 0 and 12. The 1st string (high e) is at the top, as in the app. The root is filled.
Open it in the app: 2. Intervals
The other intervals