> The startup, which launched from stealth today and graduated from Y Combinator’s tech accelerator in 2018, developed a synthetic, lightweight stone material s

> The startup, which launched from stealth today and graduated from Y Combinator’s tech accelerator in 2018, developed a synthetic, lightweight stone material similar to Corian, a material sometimes used in countertops. As the material is printed and exposed to light, it creates a reaction that immediately hardens it. “It literally freezes in air,” says Solonitsyn. It can support its own weight, making it possible to print horizontally in the air. This seems like the most interesting part; they're using a new material rather than just coming up with a new kind of 3D printer. The obvious follow-up questions are whether it's cheap enough, or strong enough, or environmentally sustainable to manufacture on a huge scale, and whether the material has a long usable lifetime and doesn't have flammability issues or off-gas any unpleasant chemicals.