New type of 3D printing uses sound waves to build up objects
3D printing typically involves depositing layers of molten plastic, laser-melting powdered metal, or using UV light to harden gelatinous resin. A new technique takes yet another approach, however, by utilizing sound waves. Developed by a team of scientists at Canada's Concordia University, the technology is known as direct sound printing (DSP).
https://newatlas.com/3d-printing/direct-sound-3d-printing