Are the predictable repetitions of pattern the safe stuff of wallpaper, or an expressive avenue for abstraction? The Portland Art Museum's recently opened Camouflage exhibition suggests that the latter is true. Featuring eight works by five artists, the paintings use pattern in a way that obscures its essential quality. That is: Monotonous construction transcends itself, creating compositions that are more than the sum of their parts. The best illustration of this is a monumental Andy Warhol canvas, for which the show is named. Stretching 37 feet, "Camouflage" is exactly what it claims to be: a mottled overlay of military-issue browns and greens, where each uniquely shaped color swatch reappears throughout the canvas. Certainly, it's a kind of final statement of irony for an artist so obsessed with repetition and color. But it also embodies the exhibition's central tension, straddling a line between self-signifying decorum and sublimated expression.

Philip Taaffe riffs on Warhol's mechanical technique, but in a far more painterly manner. In "California Kingsnake (Ringed Phase)," a single image of a snake is screenprinted across the canvas. But in the chaotic overlapping of its kinked body, the tangled chain-link composition becomes the focus and the image of the snake a mere vehicle.

Only "The Kingdom of the Father," a stunning new piece by Damien Hirst, uses pattern to venture into overtly conceptual territory. On three canvas panels which unmistakably conjure stained glass cathedral windows, Hirst has meticulously created a symmetrical mosaic of butterfly wings. Ranging from azure blues and jade greens to brilliant oranges and yellows, the wings are staggeringly colorful. This work, though, does not wear its meaning on the surface, but points, in typical Hirst fashion, to a multiplicity of meanings beyond it. On the one hand, the extravagant beauty of the butterflies appears to be a testament to the existence of God. But that sentiment is contrasted in the deeply scientific process of collecting, organizing, and displaying the specimens. Apart from fitting into Hirst's well-established groove of morbidly juxtaposing science and spirituality, "The Kingdom of the Father" reveals the expressive formal potential in pattern. As balanced and exactingly placed as each butterfly wing may be, it was, after all, chosen by the artist's hand.