3D printing two-bedrooms houses in 24 hours

In Nacajuca, building a home with Icon’s Vulcan II printer looks much like a massive soft-serve ice cream cone: Layers of lavacrete, the company’s proprietary concrete mix, are poured one after another in long swirls. The printer is controlled by a tablet or smartphone, requires as few as three workers and can complete a home in less than 24 hours.