Burning Man, that famous counter-culture gathering in the hot Nevada desert, is not just for hippies, said Jacks Valley resident Eric Matus. It's for engineers, tradesmen and fabricators who want to unleash their own creative energy in strange and vivid ways.Call it folk art, car art, steampunk, whatever. Proof of the enterprise was sitting in the side yard of Matus' home Thursday morning, as if heralding the start of the week-long celebration. The proof was 28 feet tall, 60 feet long, and 14 feet wide. Matus and friends have named it "The Pervertical Playground."While the pun on "perverted" might seem …