Artist Mary Ehrin, a protegé of Clark Richert, made her initial claim to fame with feather paintings, one of which is in the Denver Art Museum's collection. In recent years, she's turned to installations of three-dimensional objects that, like those earlier works, refer to stylish garments and accessories. In Mary Ehrin: Rockspace, at Rule Gallery, viewers passed through a lattice-work gateway to enter a space filled with imitation rocks placed on white laminate stands. The phony rocks were covered with luxurious fabrics, including metallic and leather materials. They looked positively swank and very otherworldly — like swatches from the costumes in a Star Trek movie.