Imagine a set of facing curtains, each 21 feet tall. There they stand defining a “stage” below the skylights at Suyama Space, where the sun’s rays can play against their ripples and seep through their doorways and behind them. “OK,” you say, “nice image.” But this is more than that.

The curtains, which make up Ian McMahon’s installation “Cascade” at the Second Avenue space, are actually made of plaster and both of them are free-standing. They hang from no rods, are attached to no walls. Suyama Space curator Beth Sellars refers to them as an “uncanny ghost form suspended within the architecture.”

When McMahon met with Sellars last December to discuss the project, he was taken with the space, dramatically lit by skylights. He saw the potential for the light enhancing his work as the sunlight changed throughout the day and could filter through some of the undulations in his plaster forms.

McMahon worked on site nine hours a night for five nights to create curtains that appear to be made of fabric — fabric that mysteriously stands on its own. He sprays a very strong, quick-setting industrial plaster onto rubber molds to produce his works. To the human eye, the plaster on the side that adhered to the mold does indeed appear to be made of cloth.

For this piece, he started at the bottom, applying 2,000 pounds of plaster, layer by layer, onto each mold. First, he had to build scaffolds. These are still in place, providing an additional architectural element to the work.

The back of the curtain, the side facing the scaffolding, bears all the lumps and dribbles of the spraying process. This makes it slightly reminiscent of a natural cave or grotto, quite a contrast to the delicate fabriclike texture on the other side.

The viewer approaches his stage from the back, going past the scaffolding and the curtains’ rough side, then through their opening and into the space where they appear to be thin and delicate. Somehow your sight has tricked you. Your mind and eyes are giving you different information. That disconnect delights the artist.

As are all exhibits in Suyama Space, this one is site-specific: created within the gallery and destroyed at the end of the show. The New York-based artist will return to the space in August, and with one or two mighty blows cause each curtain to cascade onto the floor in a pile of broken plaster bits.

McMahon received a master of fine arts in ceramics from Alfred University in western New York state, and an MFA in sculpture from Virginia Commonwealth University. All of his work is temporal, existing only in pictures after its exhibition. The artist believes that destruction is inevitable for all things.

“Each destruction gives rise to a new beginning,” McMahon says, suggesting that their temporality makes their destruction really powerful. “It says something about the effort, the art, the concept, the material — all to be destroyed.” Often he makes the destruction of his pieces a public event.

McMahon thus challenges the permanence of art and the permanence of place. As viewers we must observe carefully, make the most of the experience. It is offered but briefly.

Nancy Worssam: ngworssam@gmail.com