If you find yourself on Madison Avenue in the next month or so and you're suddenly enveloped in a crush of pedestrians, many of whom are parents shepherding herds of young girls, you've probably stumbled onto one of the Upper East Side's holiday traditions: department store window makeovers. These are usually cutesy confections with animated Christmas trees and poofy dresses. That's what makes French new media artist Joanie Lemercier's new window installations for Barneys so interesting: they hint at something deeper and far more chaotic than joy and good cheer.

In the first window, visitors enter a crystalline golden structure to view a kind of diorama: a dense city is built atop an angular cloud of folded paper suspended in nothingness. As we watch, a virtual sun projection-mapped onto the sculpture, casts a glow on the city, moving across the miniature sky. Gradually, the city is etched in a grid of golden light. The next window could be a nightmare disco—it's a reverse mountain, the underside of that floating city-island, that's covered in tiny mirrors, bouncing reflections back at the glass. The last window is vertigo inducing: a one-way mirror looks into an immersive landscape of angled mirrors that bounce into infinity, lit by animated LEDs. 

Lemercier is not the kind of guy you would expect to find amidst the racks of luxury-brand clothing at Barneys. When I met him at the store one morning, he wore baggy black pants and a simple button-up shirt and spoke enthusiastically about his creative process and the collaborators he brought on to complete the project, including artist Kyle McDonald and producer Julia Kaganskiy.

"The three projects are divided into three chapters," Lemercier explained. "In chapter two we zoom into the floating city structure. The more you zoom into the matter, you realize it's not exactly what you thought it was." Moving from the paper of the first windows to the mirror facets of the third is like looking at your skin and realizing it's made of atoms of molecules, he said, comparing it to the Eames's famous Powers of Ten video.

Unlike other Madison Avenue displays, Lemercier's window rewards repeated watching. The projections in the second window are generative, created anew each time by a computer program. "You're never going to see the same thing twice," the artist said. Another breath of fresh air? There are no clothes in the window displays, anywhere.

The installation, which also includes Barneys first-ever in-store gallery, is a collaboration with Jay Z, who curated a controversial holiday collection for Barneys that includes a full-face ski mask (think Spring Break) made of 100 percent cashmere, a potent mashup of high and low culture that's perfect for Barneys—crass and luxurious all at once. Thankfully, Lemercier's windows provide a brief respite from holiday commercialism with its opposite: a kind of psychedelic dematerialization.

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