In Dona Nelson’s magically messy paintings, the back is as revelatory as the front

Mathematicians often talk about the elegance of their work, especially when they solve complex problems with streamlined equations, transforming chaos into order, confusion into beauty.

That does not happen in “Painting the Magic Mountain,” Dona Nelson’s magnificently messy exhibition at Michael Benevento Gallery in Koreatown. The niceties of refinement get tossed out the window. Ditto for neatness and the loose ends it eliminates. Not a whiff of preciousness is to be sniffed among the Philadelphia painter’s 18 canvases.

Each of Nelson’s works hits like a 280-pound linebacker. There’s nothing subtle about their impact. It’s swift and vicious. It scares off viewers who want abstract paintings — especially abstract paintings made by women — to be safe, well-heeled embellishments seen and not heard, like necklaces and dresses.

But Nelson’s paintings are magnetic. They draw you into worlds where lots has happened. Time spools slowly and cyclically when you fall into their orbit. Sparks fly. Insights happen.

Three canvases hang on the wall, like paintings usually do. The rest are off the wall — literally and figuratively.

One hangs from the ceiling, like the misbegotten offspring of an overhead sign and a room divider. Three stand on metal legs, like crowd-control barriers. The remaining 11 are flush with the floor, like bollards, gravestones or flesh-and-blood people.

The paintings in the last two groups show their backsides, as if mooning viewers. “Forget transparency,” they seem to shout. “Looking at things from different perspectives is revelatory.”

On both sides of their vigorously worked surfaces, paint takes myriad shapes.

Stained into the weave of the canvas, it is atmospheric and ghostly — sometimes lyrical, sometimes haunting, sometimes melancholic, sometimes dreamy. Puddled in crusty accumulations, it has the presence of scabbed-over injuries, larger-than-life-size wounds that are well on their way to healing but still painful to experience — firsthand or otherwise. Jagged shapes, with smooth surfaces, recall old scars.

Nelson does not use many materials. To the standard trio — paint, canvas and stretcher bars — she adds only string and cheesecloth. But she does unexpected things with them, drawing or sculpting with both.

She dips lengths of string into buckets of brightly colored paint. After the strings dry, she treats them like industrial-strength stitchery, pushing them through her canvases to form abstract patterns. Whatever compositions take shape on the front are related to whatever takes shape on the back — not as opposites, more like echoes.

Nelson also soaks strips of cheesecloth in buckets of gel medium and then “glues” the strips to her canvases, where they dry to form grids and squiggles. Some are symmetrical and appear to be machine-made. Others are organic, as if modeled on the iridescent trails slugs leave on sidewalks.

Most of Nelson’s low-relief ridges also function as ad hoc molds, into which she pours and puddles viscous pigments. She leaves some cheesecloth ridges in place, like custom-made frames for miniature paintings. She rips off others, leaving ghostly halos or strange, painterly tan lines.

No two paintings are made the same way. Nelson’s process is a nonstop improvisation in which materials get piled up and torn off — recycled, reconfigured, repurposed.

Primal soup comes to mind. So do leftovers, long hidden in the back of the fridge. Nelson, never squeamish, embraces both. Unafraid of ugliness, her paintings push through the murk to bring visitors face to face with a kind of beauty so brutal it seems more at home in the wilds of nature than in the mannered confines of contemporary art.