A "shuffle blues" speeds along at up to 135 beats-per-minute while swinging the beat (swinging-the-beat means lengthing the down-beat and correspondingly shortening the up-beat--so that "one-and two-and three-and four-and" ends up sounding like "dash-dot dash-dot dash-dot dash-dot".) Optionally, the second bar can go to the IV-chord, before two more bars of I-chords in bars three and four, but more often the harmony just stays on the I-chord for bars one through four (that's what the jam mix "Looking Up" does). In bars five and six, switch to the IV-chord, before going back for two more bars of I-chords in bars seven and eight. Then descend from a bar of V-chord in bar nine, to a bar of IV-chord in bar ten, to a I-chord in bar eleven and back to the V-chord for bar twelve.
