Welcome to... "Micro-Lesson 292"
The chord progression operates between the 4th string and the 2nd string centered upon the, 7th fret, "D Major," barre chord. In measure one, we go off of the, "D and G," major chords in 7th position using a, "D Major Pentatonic," lick to connect into the next measure.
Here, the "A and D," major chords start the measure off by pulling us through with an arpeggiated, "G major," triad into the, "A Major" triad. In measure three, we apply the same, "D and G," major chords found in measure one. However, in the second half of this measure (beast 3 and 4) we apply a nice double-stop slide riff off of 3rd and 2nd strings.
The final fourth measure performs a two-chord turnaround riff using the triads off of, "G and A," major. The voicings used in this turnaround are found lower down on the neck and take us into the 2nd position.
This progression is a fun application of the 4th string major triad shapes that applies a lot of common harmony from these 4th string 3-note style chords. These shapes are both important, as well as, being very popular patterns that all guitarists should be familiar with. If these shapes are new, then use this progression as a way to become more familiar with the patterns. Memorize the shapes and turn on a metronome or drum machine to keep in perfect time. Enjoy!
Micro Lesson 292: "D Major" Triad Progression