When BioMed Realty asked Sosolimited, a design studio in Boston, to help create a sculpture for the atrium of its Cambridge, Massachusetts offices, the designers felt like they'd been handed a riddle. The realtor wanted something that could fill the space while still preserving the natural light and architectural vistas afforded by its openness. At first, it seemed impossible. “You put one large object in there and suddenly all of the sight lines are gone,” says Jeff Lieberman, founder of Plebian Design, who worked with Sosolimited to develop the idea. “It feels really opaque.”

To crack the riddle, the project required a team of creatives including Lieberman, Sosolimited and Hypersonic, another design outfit with experience in large-scale installations. They call their solution Diffusion Choir. It's a kinetic sculpture made up of hundreds of small, origami forms that shrink and expand, appear and disappear, to produce large-scale shapes that are simultaneously spellbinding and transient.

Viewed as a whole, the piece is designed evoke the mesmerizing formations commonly observed in flocks of birds. But its 400 Tyvek components—which dangle from the atrium's ceiling in a slanted, three-dimensional grid—are equally captivating. Each one can assume a wide range of shapes. At their most compact, they look like tightly folded paper airplanes. As they open, via tiny motors that push and pull the material, they start to resemble umbrella canopies. Lieberman compares the mechanism to a wine opener whose arms rise as you twist the screw into the cork. “That’s almost exactly what's going on here, except there’s a motor turning the bar in the middle instead of your hand,” he says.

Their final shape is the result of months of experimentation. “We must’ve gone through hundreds of different ways to fold Tyvek,” says Bill Washabaugh, who worked as an aerospace engineer at Boeing before starting Hypersonic. The geometry needed to be robust (each element opens and closes roughly 1800 times per day—that's a million cycles every year and a half), so the teams took cues from nature, examining the way birds stow their wings and jellyfish gently fold into themselves. The designers determined keeping the origami as simple as possible was their best bet. “This is a 10,000 part assembly, Washabaugh says. “It’s amazingly complicated; as far as we can tell this is the simplest way to put it together.”

The 60-foot sculpture is almost constantly moving. It’s powered by software that tells each component when to open and close, creating a choreography that Eric Gunther, co-founder of Sosolimited, describes as an echo. "You’re kind of seeing the ghost of an invisible flock of birds flying through the sculpture,” he says. At the top of every hour, the birds coalesce and perform a synchronized dance. But then their algorithmic behaviors diverge, and each bird performs a choreography of its own. “You can sit and watch this for hours and it won’t ever do the same exact thing,” Gunther says.