The perfect 4th on the guitar
5 semitones · P4 · C → F
Its character, in the app's words: suspension; an octave wider (P11), contemplation: the suspension becomes space.
The shapes on the neck
- On the same string: 5 frets up.
- On the next string, towards the 1st: the same fret; 1 fret 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 perfect 5th: 5 + 7 = 12 semitones.
The root is the C on the A string, 3rd fret; the other circles are the same note, F, 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