Riff 1
G-------4-5-----        X2 
D--4-7------7-4-
A-5-------------
E---------------

Riff 2
G--4-7-9-10-9-7-4-      X1
D-5---------------
A-----------------
E-----------------

Riff 1
G-------4-5-----        X1
D--4-7------7-4-
A-5-------------
E---------------

Riff 3
G----------------       X1
D----------------
A--4-7-4---------
E-5------3-2-5-3-

Riff 1
G-------4-5------       X1
D--4-7------7-4--
A-5------------5-
E----------------

i dont know, it sounds a little bit like the blues, but its a great excersise