In Lesson 9 you were introduced to a pattern on the fretboard which enabled you to play 12 bar Blues in any key (by transposing). This pattern involved the I, IV and V starting notes being played on the 4th and 3rd strings as such:
Another commonly used pattern starts on the following notes:
In this pattern the riff notes of the IV and V chord are an octave lower than if played using Blues pattern one.
Play the following half bar riff (i.e., play it twice each bar):
For a Blues in D starts at the 5th fret of the 3rd string for the D ( I ) chord, the 3rd fret of the 4th string for the G ( IV ) chord, and the 5th fret of the 4th string for the A ( V) chord.