For two decades, the London-based artist Rachel Whiteread has made a career of her signature castings of empty spaces. "Ghost," the first of these pieces to garner major critical attention, was a casting of a Victorian parlor room. As gray and monolithic as a monument, it turned a site of private, day-to-day activities into a kind of fossilized version of life. With the Turner Prize-winning "House," which publicly presented castings of three stories of a Victorian row house, and her solemn Holocaust memorial in Vienna, the artist has continued to mine the same basic concept: giving form to absence. Of course, much of what makes Whiteread's project so intriguing is its inherent failure. After all, trying to wring the secrets from an empty room through casting may quantify that space, but the resulting object is just as mute and unyielding, just as tight-lipped about what it represents.

Support The Portland Mercury

In "Untitled (Hive) I," one of a handful of minor sculptures and works on paper now on display at the Portland Art Museum, Whiteread presents a resin cast of what could be a dollhouse. Lager-amber and as turbid as glycerin soap, the piece implies transparency, as light spangles throughout the structure. However, one can't see through it; if not as densely composed, it is just as opaque—and thus inscrutable—as all of her work. In fact, this exhibition sees Whiteread parlaying that tension between shell and contents into uncharacteristically domestic terms. Several of her recent works feature castings of cardboard tubes and rolls, cardboard boxes, and pebbly Styrofoam packing—the disposable stuff of gift wrapping and packaging. Suddenly, the act of imagining what an unopened parcel holds is likened to Whiteread's impulse to substantiate the unknown. Here, she groups these castings in decorative configurations, not unlike mantel displays of bookends and bric-a-brac.

In "Juggle II," two chunks of Styrofoam flank a stack of multi-colored cardboard roll castings. With its cheery palette of fleshy peaches, goldenrod, and chalkboard green, the piece seems wired with a lightheartedness and satisfaction in small things unlike the artist's most famous work. In contrast to the grand gestures of her massive projects, this work looks inward. Granted, it's still as poker-faced about what lies there, but it appears Whiteread is finally at home in that not knowing.