Is there anyone on this BBS who's a fanatic about old blues music? Specifically, I'm looking for prior art on a certain guitar or bass riff. Let me explain:

I've just co-written a song with a friend. It's a very bluesy song, and the verses do a thing where she sings a line, then I play a riff, then she sings a line, then I play a riff. As I was messing around trying to come up with a good catchy riff, my fingers fell into an old familiar pattern: The opening riff for the Rush song "What You're Doing", off of their first album. She instantly fell in love with it, and wants to use it in the song as-is, despite my protests that I don't want to copy someone else's riff.

The rest of the song we've written is nothing like that Rush song. Even the riff itself is played in a different key and with a different rhythmic pattern. But the notes are more or less the same, and they resolve the same way. If you know the Rush song, it's clear that I'm doing the same gag.

So I asked another friend about it, and he said the Rush riff isn't even theirs, that it's likely an old classic blues riff. Although he doesn't have a specific example to offer as proof, he seems pretty confident about it.

So. If you're an old blues fan, could you give a listen to the riff in question, and see if you can come up with another example of it? The riff can be heard in the album's song samples at amazon, it's track number 5.

(I'd offer a sample of our song, but it's not ready for public consumption yet. The Amazon sample should be enough.)

So, anyone know of a similar riff elsewhere?