Watch the Straight Down online guitar lesson by Joe Dalton from 50 Acoustic Blues Licks You MUST Know
Here’s a totally different groove. This one works great in a straight rhythm. Of course, you can also play this as a shuffle. I've used something like this to back singers and soloists, but it can also stand on its own as part of a blues solo chorus. The open D and G are the flatted 7th and flatted 3rd. These are the notes that define the mood of the lick.