The fact that Sabbath went from waxing philosophic about marijuana on Master of Reality ("Sweet Leaf") to cocaine on Vol 4 ("Snowblind") betrays how the shift in drug consumption profoundly altered the group's sound. Where the former LP feels earthy and warm, the latter is cold and electric (yet no less heavy). The violently propulsive "Supernaut" contains one of guitarist Tony Iommi's best riffs. By record's end, the manic and disjointed "Under the Sun" / Everyday Comes And Goes," the band invents punk and thrash while Ozzy howls, "Every day just comes and goes / Life is one long overdose."