On a Saturday night in summer 2013, architect Platt Boyd was working late in his Alabama office. He was reading an article about construction, specifically the kind the ancient Egyptians used for the pyramids by building a monolithic structure, layer by layer.

Three years later, with co-founder Chris Weller, Boyd is doing just that using 3D printing technology.

“It started with a sketch and 3D printing with different mock-ups along the way,” says Boyd of the inspiration his joint venture with Weller. “That was when I was an architect and had been with a firm for 15 years.”

He left the firm in April 2014 to found Chattanooga, Tenn.–based Branch Technologies with Weller, a colleague from architecture school. The pair set off to answer this question: “What if you could use 3D printing just to create the shape and let that be the scaffold?” asks Weller. “This open structure could be filled in with other materials like concrete, insulation, utilities. We started talking about the idea of growing a building instead of building it.”

That’s where nature came in.

“It’s an idea that happens in a natural way on a cellular basis,” Boyd explains. “The bond of the cell creates strength, but the filling provides the majority of the strength. And cells use economic materials to fill themselves. Our idea learns from that. We use 3D printing to create that complicated wall assembly but then use filler materials. You know it works; you see it every single day in everything around us—in trees, in our bodies, in rocks. It’s intuitive.”

Adds Weller: “Our technology is a way of imitating nature’s creative process and applying it in human design. Take a look at the structures and mechanisms at work inside almost any living thing and you’ll find an ingenuity far more profound than that of any human invention. Life hinges upon finding optimal balances between risk and reward, form and function, efficiency and resilience.”