i've taken the actual riffs from a book by marius popp 
(the most gifted romanian living jazzman, quite a 
teacher and pianist). they 
are:
   -- one clock jump / count basie
   -- blues in the closet - oscar pettiford
   -- sud - west funk / donald byrd
   -- sack o'woe / cannonball adderley
   -- bag's groove - milt jackson
as you can well see here, the riffs cover 4 or 6 
measures; that's why they're repeated, to cover all the 
12 bar sequence (and, by the way, 12=4*3 or 6*2!)
the rhythm track isn't strict. i've changed key in all the 
places where this was necesary; the point of track 3 is 
for you to get the key and the progression, whose 
general formula is:
i7 iv7 i7 i7 iv7 iv7 i7 i7 v7 iv7 i7 i7
(i is the key or root chord, you may use any; the most 
frequent are C, E, F or A.; iv is the subdominant - a 
fourth above and v is the dominant, just a fifth above 
the root chord)
e.g E7 A7 E7 E7 A7 A7 E7 E7 B7 A7 E7 E7
is quite a blues progression, built in E.
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great thanks for the funky rhythm that i've worked on 
here in this tab (it's from Leonardo_800).
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the purpose on which i've made this tab is for you to 
learn how to impovise along with these riffs. feel free to 
change the instruments (like piano, rock organ or 
anything else) and use the minor blues scale (from 
'scales', in the 'tools' menu). while playing, try to 
change the scale you're using according to the 
current chord (for the example above, use the E minor 
blues scale in the measures in E - 1, 3, 4, 7, 8, 11, 12, 
A minor blues scale in A - 2, 5, 6, 10 and B in measure 
9). good luck to you! if this tab's useful to you, sumbit 
your impression, please... do you like the drums?