Watch the Less Is More online guitar lesson by Brad Carlton from Chord Studies: Double-Stops Vol. 1
Again here we'll use the interval of a third in the key of A major. This first double stop you can clearly see is derived out of our A barre chord form. All we're doing here is playing adjacent intervals of thirds out of the major scale in double stop form. You could play these as full chords, but sometimes less is more so try this one out.