Lining two walls of the Portland Art Museum's recently opened exhibition of work by the abstract sculptor Ursula von Rydingsvard are a series of new charcoal drawings. With titles like "Roman Lace" and "Clothes to Dry," these delicate, almost ephemeral compositions seem to run counter to the monumentality of the enormous cedar sculptures she's best known for. But the longer one examines these abstract images, the more similarities begin to emerge. Firstly, the surfaces are as painstakingly worked as her sculptures, in which she laboriously rubs powdered graphite into cedar beams. Not only does her expressive cross-hatching seem to dance across the paper, but smudges, erasures, and adhered bits of paper add tremendous depth. More importantly, the monochromatic palette casts an oppressive tone of darkness and dread on these sketches.

This sense of confinement and claustrophobia hangs over the majority of work by von Rydingsvard, who was born in a German refugee camp in 1942 after her parents were forced to flee Poland four years prior. In particular, the monolithic cedar sculptures she has been making since 1976 exude this suffocating weight. One such sculpture, "Pod Pacha" from 2003, is the exhibition's undeniable centerpiece. Composed of 4" by 4" beams, which von Rydingsvard has glued and clamped together, this hulking structure is propped up on 15 roughly carved legs and encloses an audible motor that repeatedly threatens to lift the piece's lid-like top. More spectacle than traditional art object, "Pod Pacha" is grotesque and monstrous, but its sheer inscrutability seduces viewers into contemplating all of its possible meanings. In that sense, the sculpture presents itself as a kind of unsolvable riddle: It flaunts the promise of some withheld secret, while frustrating with its refusal to disclose it.

The piece's central tension lies in its conspicuous juxtaposition of organic and industrial forms. Not only does the sculpture appear to be entirely made of cedar, but, as a rich, woody aroma fills the installation space, the viewer is also cued to draw this conclusion through sense of smell. But von Rydingsvard, who has also used such organic materials as animal intestines and peat moss in her sculptures, complicates this sensory information with the disruptive crank and whir of a motor, noisily working inside the massive container. As a result, these contradictory messages generate scattershot interpretations. Its size and shape connote a dumpster or trash compactor. But as the lid bucks and strains, the multi-legged sculpture could also be read as some kind of beast. Or are the regular intervals at which the lid rises and falls meant to signify breathing? Or is it a symbol of entrapment, in which the structure contains some entity struggling—and ultimately failing—to escape? In this sense, the "Pod Pacha" operates within a poetics of failure, alluring viewers with its elusiveness. As it raises far more questions than it answers, the sculpture becomes a kind of negative signifier. Its limitless potential interpretations reduce it to an enigmatic thing, so full of meanings that it becomes meaningless.