My Young Guitar Student Discovered Something

My student was playing a melody on the B and E strings.

He discovered he could play the same pattern of frets on the D and G strings, resulting in the same melody in a different key.

I pointed out that he could also play the same pattern of frets on the A and D strings.

And on the E and A strings.

The only pair of strings where it wouldn’t work was on the G and B strings. He would need to move each note on the B string up 1 fret.

This simple discovery unlocks a deeper understanding of the fretboard.

It leads to the realization that the interval between each pair of strings is a perfect fourth, except for the G and B strings, which are a major third apart.

When you understand that you can move a melody to any pair of strings (even the G and B strings with a slight adjustment), it gives you greater freedom in exploring the guitar.

What discovery has helped you to understand the fretboard better?