This exercise is based on RLR. The pattern of this Groove Exercise is played in 16th notes or in 32h notes. This is making the pattern of 3 notes shift in a nice way. Try to add accents to phrase the pattern you want it. Unfortunately the video is not high resolution but it stil gives a good impression. Use the stroke in your own way. As you can hear I am starting the stroke in different places. Not always on the first beat. Sometime before the first beat or half way the measure.