Look Outside Your Window is not a Slipknot album. But it is the side effect of one. “If Slipknot hadn’t been in there, we would’ve never done this,” says M. Shawn Crahan , who’s best known as the long-running Midwestern metal band’s percussionist “Clown.” “A little bit of what’s going on down there is the reason this could go on up here.” He’s talking about the recording of Slipknot’s fourth album, 2008’s All Hope Is Gone. That’s when he and several of his bandmates unmasked and picked up