OK....very limited music background. Have been noodling on dulcimer for years and love me the diatonic.
Just learning about pentatonic. Thought "That's cool. Can I make a pentatonic fretboard? No joy. I think I might be beginning to understand. Forgive me if this sounds super weird, but it's the way my brain works....
Diatonic de-constructs the chromatic with the removal of frets.
Now what I think pentatonic does is more like a sliding scale. To illustrate, while diatonic is a physical construction, is pentatonic more like an overlay onto chromatic? Like in secret codes, you can lay a sheet of paper with special holes on it over a specific page in a book and read a secret message through the holes.
So I guess what I'm asking is while diatonic is physical, pentatonic is more like a relationship between the chromatic fretboard and your actual fret starting point on the fretboard.
Is that clear as mud?