Every building you’re in makes you do things; architecture stages you. Two 20-by-40-foot stage curtains made of ghostly white plaster are the latest installation at Suyama Space, the art gallery in a downtown architectural firm. Incredibly, the curtains stand on their own. They’re toweringly fragile. Upstate New York–based artist Ian McMahon had to invent the techniques and machinery to make them—they’re so unlikely that the architects didn’t believe they would ever stand. In a few months, they’ll be destroyed, plaster turned back to dust. The end. (Suyama Space, 2324 Second Ave, suyamaspace.org, 9 am–5 pm, free, through Aug 15)