Two walkers’ interaction leads to orbiting —Naresh Sampara (University of Nottingham)

A millimetre-sized oil droplet can bounce on a vertically vibrated liquid bath for an unlimited time. It may couple to the surface wave it emits; leading to horizontal self-propulsion called walker. The interaction of the two walkers leads to orbiting with each other.

https://downloads.sms.cam.ac.uk/3317733/3317741.mp4