If you’ve been watching the contemporary-art horizon for the past 20-plus years, the passage of another Raymond Pettibon show might seem as remarkable as another Space Shuttle takeoff, or another Britney Spears meltdown/comeback — notable, but momentous mostly for devotees. With a kind of skid mark–pop style locked in as a signature since his days illustrating flyers and album covers for his brother’s band, Black Flag, and the SST Records label in the ’80s, the evolution of Pettibon’s work has felt glacial despite its often incendiary content. And while at its best, his work has offered a blend of smartly targeted appropriation and highly original imagery with naggingly troublesome captions and imbedded texts, the lesser of his output has been redundant, self-plagiaristic and sophomoric fiddling around. None of that, however, makes his latest outing — Part 2 of an exhibition, the first part of which focused on early works — a show you can afford to miss. While collage has been part of Pettibon’s bag of tricks since the ’80s, the tool is unleashed here to jarring, even violent ends, and Pettibon’s expansion of his painting prowess and color use amps up jumbles of images and texts that, even when they remind you of the sardonically amusing Pettibon of old, are more complex and provocative. Pettibon’s new work blends the acute and the astute with the jagged and the blunt as it cuts into the history and pathology behind our current state of fucked up–ness, but it also carries with it a sense of optimism that comes with what seems a very genuine response. Pettibon is an artist who has noticed that Rome is burning, and he isn’t fiddling anymore. Regen Projects II, 9016 Santa Monica Blvd. (at Almont Dr.), L.A., Tues.-Sat., 10 a.m.- 6 p.m.; through Jan. 24. (310) 276-5424 or www.regenprojects.com.