ooh! That is good. Also, I just found a pic in S & B Happy Hooker, of herringbone half double crochet - it looks a lot like the blanket pic. I googled and got quite a few hits for videos, but none of them panned out. But I think the directions in S&B are fairly straightforward so I will give it a shot and report back!
Oh, and I just saw your comment on angularity - I mean, the yarn goes at an angle back and forth, not just straight up and down. If that makes sense!