I was watching this video of Jerry Portnoy playing with Rick Estrin and the lick at around 1:20 caught my attention. It’s a very cool example of using the octave notes available on the one and four holes.
Doing this kind of thing is much easier if you use a technique David Barrett calls tongue switching. Basically all you do is shift your tongue from the left side of your mouth to the right, so the air goes through the one hole instead of the four. Easier said than done to begin with but it’s a technique well worth learning as it opens up a lot of very cool licks, especially in the I, IV, V part of the 12 bar blues.