People usually try to avoid having jets collide in midair. But Claas W. Visser and his colleagues at the University of Twente have found that colliding jets of liquid with differing surface tensions opens a new avenue for 3-D printing (Sci. Advi. 2018, DOI: 10.1126/sciadv.aao1175). The technique is gentle on living cells and prints biocompatible polymers, which could be useful for tissue engineering. Learn more in this video.