If you experience any technical difficulties with this video or would like to make an accessibility-related request, please send a message to [email protected]. Research at the University of Chicago and the University of Santiago in Chile has identified some general rules that apply to wrinkling and folding in materials of widely varying thickness and composition. This 41-second video, taken with the aid of fluorescence microscopy, shows the folding of microscopically thin lipids (fats) under horizontal compression.