This is something I like to give students after they've advanced through SEVERAL different 16th note based strumming patterns. It's basically a polyrhythm that starts each bar/measure. You have 4 chords evenly spaced across the first 3 beats. Beat 4 is just a quarter note to give the brain a break from playing the polyrhythm.
Here is the Guitar Pro 6 tab for this lesson:
John Taylor - guitar and bass instructor for Mile High Shred.