My brother’s lab (not at MIT) has been 3D printing optically clear glass for years. They can do all sorts of shapes and figures, though I’m particularly fond of the Yoda heads. If I’m reading this article correctly, the breakthrough they made was with the temperatures they can do it at, and it’s much less to do with the novelty of 3D printing glass. So it’s much less “hey, this is amazing, nobody has ever done this before,” and far more “we did this cool thing in a new and harder way!”