Relatively straightforward approaches—diagrams as a means of mapping space—come from artists like Öyvind Fahlström and Barry Le Va, who map out their plans for, respectively, the 1966 Venice Biennale (a sprawling, madcap installation called Dr. Schweitzer’s Last Mission) and the 1995 Whitney Biennial (a mass of barely distinguishable shapes). Architect Steven Holl looks at how light and water would circulate in his extension to Kansas City, Mo.’s Nelson-Atkins Museum in one tiny drawing. Conceptualist Mel Bochner describes a piece involving 48-inch lines scattered all around a room in another.

One of the diagram’s most intriguing aspects is how it allows us to see a mind at work, thinking things out on paper, unconcerned about whether others will find that thinking coherent. Wolfgang Tillmans’s diagram is a tangle of words and lines that he made while planning the catalog for his 2003 exhibition at Tate in London; Julie Mehretu’s Migration Direction Map (1996) is a fascinatingly opaque set of nebulous shapes and arrows mapping out the increasingly complex, furtive forces shaping contemporary society. Joseph Beuys’s 1977 lithograph Letter From London makes one wish he were still around to explain what his simple but obscure diagram about “myth” and “synthesis” means.

Diagrams can easily leap time and space, bridging unlike ideas and giving form to otherwise impossible notions (Carolee Schneemann’s comical, frightening 1966 Parts of a Body House (Genital Playroom)), or invisible plots, as in Mark Lombardi’s delicate web of circles and lines from 1999, which lays out a conspiracy involving the Miami-based World Finance Corporation. The work, thrillingly, is a collage. He’s photocopied an earlier one of his drawings of the network, tilted it, taped it to his paper, and then drawn lines in pencil, charting new connections. His scrawls are barely legible, but you can see and feel plans for a new artwork—and, just maybe, the scheme itself—coming together in those marks. (Through April 27, 2013)

Installation view. (Courtesy Andrea Rosen Gallery)

Just how resilient is the rectangle? How many things can it be set around, and for how many years, before it loses the power to transubstantiate? For his naively broad-shouldered New York solo debut at Andrea Rosen Gallery, Aaron Bobrow scouted New York construction sites from which to wheedle, barter or borrow lengths of “debris mesh,” the tight and complex weave of steel wire that protects pedestrians from falling debris. The mesh is marked with three long parallel stripes, usually orange but sometimes sun-faded to the color of pale butter, and snagged with little rips and imperfections or, in the case of Untitled (substitution)—so titled because the artist had to trade perplexed construction workers a different section of mesh for it—two big triangular rips like eyeholes. But those stripes are pulled out of parallel when Mr. Bobrow stretches the material on enormous, double-barred wooden stretchers that look like doors or long sections of wall from some Viking stockade. (Two pieces, Untitled (exhumation) and Untitled (exoneration), are more than 20 feet long.) Across the street at Andrea Rosen Gallery’s other space, meanwhile, Jacob Kassay, in collaboration with two older artists, Olivier Mosset and Lawrence Weiner, orchestrates an even more self-referentially self-contained series of concentric rectangles, pairing one of his own framed scrap canvas pieces, a vertical rectangle with a square bite taken out of the bottom-right corner (Untitled, 2012), with Mr. Weiner’s 1968 piece, on loan from the Museum of Modern Art, A 36”x36” removal to the lathing or support wall of plaster or wallboard from a wall. Mr. Kassay’s piece is hung on, and Mr. Weiner’s cut out of, Mr. Mosset’s 2013 Yellow Wall, which is also exactly what it sounds like. As with the mesh, the transparency is only apparent: you can see right through it, but it’s still not clear if there’s anything behind it. (Through March 23, 2013)

Andrea Rosen. (Courtesy PMC)

In September of this year Andrea Rosen will open a second, 1,350 square-foot space at 544 West 24th Street, just down the block from her current space at 525, as first reported by Art in America yesterday.

Over the phone today, Ms. Rosen said that the space will allow her to continue creative curation in the vein of the project space at the gallery's current location, which is also called Gallery 2. The new space was partially taken on to show her new artists like Josephine Meckseper and Ryan Trecartin, she said, but  also allows her "to evolve in all the ways that I think are all of my responsibility as a gallerist."

When thinking about her evolution as a gallerist, she says she often returns to one of her artists, Félix González-Torres, whose estate she still represents.

"When you inspire people to have a point of view," she said, "you also create a responsibility for people to have a point of view and that sort of Félix González-Torres-ism is really at the root of what I'm interested in, and that cuts across every part of the art world."

And with Gallery 2, she said, she hopes to allow for experimentation and exhibitions at a remove from other elements of the art business.

"In one way, I don't care whether Gallery 2 shows are profitable," she said. "On the other hand, if I were to ever separate the idea of inspiration from the idea of the market," which, in the vein of Félix González-Torres, she would never do normally, "I believe that collectors, along with the public, are making a true consensus on what's significant.

"We want to be immortalized by art, and those generalizations about us, what we're leaving behind to represent us and our time, have a relationship to money in that we value them. How do we value those things that are going to historicize us? So there has to be a sense of value, but that's different from the market."

The first show for the gallery is not yet set in stone, but Ms. Rosen said it will most likely be an artist who has not yet had a solo show in New York City. The exterior of the second space, like the flagship gallery, will be green.