It's 3 strings total. E string - 1st fret / 3rd position...playing ead / then 2nd / then 1st / then open..E string is the only change. Sometimes I throw in an open G in there. It's just a way to practice something repetitive to gain skill without wanting to blow my brain out from the sound.
Please contact me if you would like to use this in a project. We can discuss the details.