Moire pattern of two overlapping circles creating a pattern of ellipses and hyperbolas. Animated in some SVG-viewing software.
<a href="//commons.wikimedia.org/wiki/User:SharkD" class="mw-redirect" title="User:SharkD">SharkD</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>