It was Shawn Lane who enlightened me to the idea of separating hammer-ons and pull-offs. Usually, guitarists link
hammer-ons and pull-offs together. However, it is possible to play lines that only incorporate hammer-ons or only
incorporate pull-offs. Below is a line in the D pentatonic minor scale that only uses pull-offs. Basically, every note is
picked in these groupings of sixes except for the second of six notes and the sixth note itself. Try the line out and
you'll see it's actually very easy to play.
Now for the ascending version. The same rules apply for this version except that we are only going to use
hammer-ons.