#1
http://youtu.be/MfFWn-8vPJ0

I want to be able to add complex riffs into my songs like the one used in that song however I don't know the theory behind it. I can copy the one used in that song by ear but I can't incorporate it in other ways. I hear those types of riffs used in a lot prog rock songs. What can I learn in order to create my own complex riffs like that?