One of the challenges of experimental fluid dynamics is capturing information about a flow that varies in three spatial dimensions and time. Experimentalists have developed many techniques over the years–some qualitative and some quantitative–all of.
Rolling Circles and Balls (Part 3 - This gadget is called a Tusi couple. You could use it to convert a rolling motion into a vibrating one using some gears. Greg Egan made a nice animation showing how:)