Watch the The Stumble: Ex. 4b online guitar lesson by Andy Aledort from Kings of Blues & Rock Vol. 8: Freddie King
A lot happens in this little eight-bar phrase: I begin with aggressive sliding triplets on the top two strings, sounding the fifth and b7th (B and D, respectively), and in bar 3 play a repeated hammer-on riff that refers directly to the IV chord, A7, followed by a very melodic riff that fits nicely over the Bb dim. chord in bar 4. Bar 5 features fast-descending sixths (two-note voicings wherein the pitches are sixths apart), and the excerpt ends with a series of open-string riffs based on the E Blues scale.