Somewhere on campus at North Carolina State University, an interesting thing happened. Researchers took a liquid metal alloy of gallium and indium at room temperature and made more than just a puddle. They made a 3D figure. They made a wire. They even made tiny letters. The remarkable occurrence was that it all held together.

The researchers have spent years developing a method of 3D-printing liquid metal at room temperature. The resulting paper, "3D Printing of Free Standing Liquid Metal Microstructures," was recently published in the journal Advanced Materials.

The process uses a syringe needle to dollop tiny spheres of metal together. A thin oxide skin holds it all together and prevents the printed structures from just collapsing into metal blobs. It can be used to create extruded metal wires or put together tiny structures crafted from spheres.