Watch the 1 Notes-Per-String Forms online guitar lesson by Brad Carlton from Guitar Lab: The Golden Arp
This lesson deals with 1st inversion one note-per-string forms of the Add 9 arpeggio. These forms are quite useful and technically accessible.
Measure 1 of ex 23 can be viewed as a 1st inversion E triad on string 5, 4 and 3 with the 9(2) added below on the 6th string. Likewise the remaining two forms can be viewed in this manner.
I suggest you play these chord forms over a backing track with an E bass note since these voicings have the 9(2), the lowest voice. This could confuse your ears if you aren't hearing the root in your head.
Measure 3 is a very useful and practical form so make it a regular tool in your playing.