Riff 1:
G|-----------------------------------|
D|-----------------------------12-14-| repeat as many as needed 
A|-----------------------------------|
E|-8-8-8-8-8-8-8-8-8-8-8-8-8-8-------|

Riff 2:
G|----------------------------------------------|
D|-14-14-14-12-12-12-12-12-12-12-12-12-12-12-12-| repeat as many as needed
A|----------------------------------------------| then go back to riff 1
E|----------------------------------------------|