The draw of these abstracts? Changing plot lines

Letting your eye rove through a large, abstract drawing by Chuck Holtzman is like cozying up with an epic novel such as "Lord of the Rings." There are switchbacks and surprises, a fascinating variety of lines, textures, and evocations of space. A shift in the drawing -- call it a plot turn; a step out of the haunted forest to find yourself on the brink of an impassable but dramatically beautiful gorge -- may shake up your vision of the piece as a whole.

Holtzman has a gorgeous show up at Victoria Munroe Fine Art. The former sculptor has, for the last several years, been caught up in creating works on paper. You can see the architectonic aesthetic of his three-dimensional constructions in these drawings: He uses drafting tools to draw perfect circles, for instance, which he tightly stacks into coils.

In some of the smaller drawings, such as "Untitled (#714)," he crowds the center of the page with these coils, making grids of them that walk the line between compulsive perfectionism and wigging out. They cluster together against a lovely mottled ground, a picture of fearful regimentation against open, unpredictable spaciousness. These are engaging but seem like experiments, samples of ideas that Holtzman brings together magnificently in his larger drawings.

"Seven Hundred," at nearly 5 feet tall by 3 feet wide, swims with concentric blobs that recall descriptions of mountains in topographic maps. These start as discrete forms, but then a line strays wildly, morphs from wavering tendril to straight arrow, and ricochets around. Or it darkens and repeats obsessively. The coil shows up as a shimmering ghost over a colony of black dots. Inky streaks look like the work of a stencil, a squeegee, or both. At the bottom, Holtzman has incised a rectangle out of the page and flipped it, inverting a piece of a black curving form so that it looks like the eyes of a masked man peering out at us.

All this takes place against a ground smoky with charcoal, which could read as the dust kicked up by all the action on the page, or as a soft open space with furrows and shadows against which all these lines and blobs heave and tangle. Either way, "Seven Hundred," with its gothic and obsessive intricacies, is, like all of Holtzman's larger works here, a piece in which to lose yourself.

German artist Heide Hatry is the daughter of a pig farmer, and she's got a farm girl's matter-of-fact attitude toward slaughter and making economical use of a carcass. Her primary material is pig's skin, which has much in common with human skin. Hatry's show "Skin" at Pierre Menard Gallery is sometimes clever, but also cluttered and too reliant on her material's potential for shock value.

Hatry also adds a confusing conceptual twist: She says "Skin" is a group show, but each of the seven artists -- she offers hair-raising photos of them with their work -- is an alter-ego of hers. Hatry has several bodies of work here, but they're cohesive enough to clearly be the work of one artist.

Her smart but harrowing video "Slaughterhouse" succinctly follows the assembly-line evisceration of pigs. There's no judgment or commentary, just the visuals. A football made out of pigskin, with staples where the stitches would be, is both creepy and funny.

She crafts hollow sculptures of infants from pig's bladder: they're brown, but translucent, weirdly beautiful , and disturbing. But "Baby with Rat" has one playing with a freeze-dried rat: It seems intended only to provoke. There are over-the-top photos of other pigskin babies wrapped in barbed wire.

Hatry didn't need to make a spook show. Skin is so freighted with meaning, it's better worked with in more understated ways.

Mario Diacono at Ars Libri doesn't have a lot of space -- one, sometimes two walls. Usually, Diacono makes good use of his square footage by mounting one large-scale painting. His new show, with work by James Siena, features a small painting.

Surprisingly, the large wall doesn't swallow it up. Siena's work, "as heads is tails," pulls you right in like the eye of the storm. He's a formalist abstract painter who creates complex visual patterns in enamel paint. He calls them "visual algorithms," and sets out detailed instructions for each one before he starts painting it, like Sol Lewitt. His work is hand-painted, without ruler or compass, and has a certain ragged, imperfect grace.

This piece features concentric red and black pathways zig zagging left and right over white ground, cinching their way around two blocks in the middle and two at the bottom, each a pair of red and black. The blocks are the anodes and cathodes of the piece, connected by these circuitous paths. The crisp yet imprecise painting appears deceptively simple, but the network it portrays is full of lovely nuances. Siena's work honors the universality of intricate pattern -- in nature and in our own psyches.