Eva Speer (no relation to Richard Speer) is a virtuoso with materials. That's her strength and weakness. She can paint up a storm in realism or abstraction, makes ravishing screen prints and is a gifted sculptor. Stylistically, she's all over the place. You leave her shows thinking: "Will the real Eva Speer please stand up?"

The Speer who stands up in her latest exhibition, Alone Together, is a minimalist whiz kid. In her mixed-media wall sculptures, Triangulation and Game #4, she layers swirly latex paint atop nubby-textured boxes made from cast resin. Sometimes, as in the cobalt-blue Echo Box #3, the transparent boxes contain blocks of wood, creating nested shadowboxes of rectilinear forms. In other works such as More or Less (Pulse), the boxes are pierced by a grille of circular holes. In More or Less (Proof), Speer fills the bottom of the box with the plastic wedges left over from the drilled holes, slyly transliterating Robert Morris' iconic 1961 sculpture, Box With the Sound of Its Own Making.

It's all very clever and technically flawless, which is no surprise given Speer's versatility. After all, this is the artist who introduced herself to the Portland art-going public in 2008 with the quietly spectacular wall sculpture Award, which looked like a soft, tufted pillow but was actually made out of hard wood. And who can forget the paintings she made last year of rolling waves interrupted by incongruous abstract brushstrokes? In those latter works, the artist found a way to successfully exploit the disconnect between the illusion of realism and the artifice of painting. The wave paintings seemed to peel back the veils of perception and let viewers in on a terrible secret: that the great and powerful Wizard of Art is, in fact, a little man behind a curtain with a fistful of paintbrushes and a bag of tricks.

By comparison to those works, the current pieces seem gimmicky: "minimalism redux" as the next stop on an art-history tour led by a professor intent on putting her spin on as many techniques as possible. It will be a good day when Speer pauses from her restless forward motion long enough to marinate in a single idiomatic style. Sometimes a virtuoso needs to stop worrying about hitting all the right notes before a song can really sing.

SEE IT: Alone Together is at Charles A. Hartman Fine Art, 134 NW 8th Ave., 287-3886. Through Sept. 28.