Chicago's U.S. Maple makes a kind of mutant classic rock in which all the usual genetic elements of rock 'n' roll are present but are scrambled around, volatile and unstable. Mark Shippy and Todd Rittman's trebly guitars squeak and tickle then suddenly erupt into orderly power chords, just as Pat Samson's drums drop out from beneath you. Al Johnson's throaty rasp--one of the great deviant voices in rock history, on par with Captain Beefheart's--often sounds like a ghost singing along with musicians who don't know he's there. This is avant-garde music, but what separates U.S. Maple from the many bands that get thrown into the post-rock slagheap is a solid, immovable backbone of rock's fundamentals, and listening to Acre Thrills gives you a sense of musical déjà vu. It takes repeated listenings to unpack all the hidden, crumpled messages within. "Open a Rose" has a twitching locked groove that could be an outtake from the Clash's Sandinista!--it's the closest U.S. Maple gets to reggae. And "Ma Digital," the first track on the album, is two or three songs at once, left in a disarming state of juxtaposition. Any of its riffs could serve as the foundation of a head-bobbing indie-rock tune, but together they're a fascinating puzzle. Most of the so-called post-rock that flourished in the mid-'90s (and now seems to be running out of steam) eschewed the basics of rock 'n' roll for the sounds of electronica, funk and dub. But U.S. Maple proves once again that rock 'n' roll will never die--it'll just get weirder and weirder. A-