Smokestack Lightning!

One riff, barely one chord.  Harder than it seems to do.  Howlin' Wolf was a literal and figurative giant of the blues.  He is as important as the great Muddy Waters to some blues fans.  This is often what I give to students as they study the E minor pentatonic scale and finger picking.  We do a version of this with the "thumb and two" technique for the right hand.