A team of physicists from the University of Amsterdam's Institute of Physics has 3D-printed a Christmas tree made entirely of ice. Researchers Menno Demmenie, Stefan Kooij and Daniel Bonn used no freezing technology or refrigeration equipment—just water and a vacuum. In time-lapse videos, you can see how the Christmas tree is printed and how it melts again when the vacuum pump is turned off. The work is published on the arXiv preprint server.
