Here are the possibilities for different intervals in D Dorian on the D and G strings.

Of course, if you have exceptionally long fingers, or a high tolerance for pain, you’ll be able to play 7ths, octaves and unisons on two adjacent strings, but for us digitally compromised individuals, we’ll be sticking to a range of 2nds to 6ths.

And even that might bring you to pray for granny’s cod-liver oil.

Keep trying, though :)

Move a particular dyad through the scale until you’re familiar with the fingering and sound.

Remember you can use any of the open strings in this particular key. Try adding the open B and E.

Sometimes you get nice clusters. E.g., if you play C and F on the 10th fret [on the D and G strings]. Then add the open B and E you get a clustery chord.

That’s a nice thing about these linear interval things: you can just move them up and down the fretboard and see what takes your fancy.

Try it.