Riff 1
G|----------------------|
D|----------------------|
A|--3--3--3--3--3-0-2-3-|
E|-3--3--3--3--3-3------|
Riff 2
G|------------------------------------|
D|------------------------------------|
A|-----33-----33-----33----33----0-2-3|
E|-33-----33-----33-----33-----3------|

Then go back to the beginning and start over.
Or just play Riff 1 over and over, it's more fun that way.