Mainly, I'm into blues, rock, punk. I've tried to jam with metal guys, and it is very confusing. Mainly, they seem to have old Metallica songs they've learned from tabs. None of it seem to have any chord structure. It seems (to me in my ignorance) to be just interesting sounds with little pattern. (Hats off to them, very difficult to play) I'm a scientist by day. Any logical discriptions or URL's or concepts, or anything I can grab on to.