Shadertoy demo: https://www.shadertoy.com/view/7ds3zB Thanks to Ravi Vakil (and his son Benjamin) for noticing the circles and asking the question, and to CodeParade (http://codeparade.net/) for the photos of the Legoland globe. Followup video answering the question about the rates of the ripples: https://www.youtube.com/watch?v=yrDbD90HXyo