In a bold, colorful etching, San Francisco–based Tauba Auerbach is beautifully ambivalent. Yes or No and/or Yes and No names the piece and translates its intent. Using 59 plates, she layered the letters atop each other, achieving a pile of color. The circumference of a yellow O seems to enclose an angular blue Y, while the N, interrupted and repeated in alternating hues, is nearly argyle, all pointy elbows. There is no bleeding of color, just an overall sense of composition, in which design signifies more than meaning. Western Bridge, 3412 Fourth Ave. S., 838-7444, www.westernbridge.org. Thurs.–Sat. Noon–6 p.m. Ends May 9.