I’ve just come across this page of wonderful animations of vortices. Maxwell would have loved the leapfrogging vortex rings. They are exactly what he tried to illustrate in the zoetrope strips he painted, and that are featured in the photo that’s currently at the top of my blog. This is the first example I know of of a moving picture being used as a teaching aid. Leapfrogging vortex rings were important to him because at the time they were a popular candidate for a model of the atom.