Something's not quite right with one of the walls in the back room at Zg Gallery. It has molding not only across the top and bottom but over the whole surface--white plaster strips, each with a different design, each tilted a bit off horizontal. And the wall itself leans backward, further unbalancing the patterns. This work, Ben Butler's Sediment, made in collaboration with Rena Leinberger, is a humorous take on excessive decoration--the patterns seem self-generating, potentially infinite. In his artist's statement Butler, one of the more intriguing young artists now working in Chicago, says he's interested in "how human creations relate to the nonhuman world." His other three sculptures at Zg, "Species I-III," are round wooden tabletops supported by dozens of hand-turned legs of varying lengths that make the tables tilt. II is larger than I, and III is larger than II--as if the individual pieces were growing in size like plants. The combination of references to geometric, manufactured forms and suggestions of natural growth creates a contradiction that deepens our awareness of the incompatibilities between nature and the industrial world. Zg Gallery, 300 W. Superior, through April 19. Hours are 10 to 5:30 Tuesday through Saturday; 312-654-9900.