Vortex smoke rings created with 3D printed wings

Dustin Kleckner sez, "Scientists tie vortex rings (smoke rings, basically) into knots using 3D printed wings. Includes high speed video, also in 3D. In addition to being very cool, they are also related to knots and braids that appear in places like the sun's surface. Full disclosure: I'm one of the scientists that did the research." The duo overcame their experimental difficulties by...