A Menger sponge with raytracing. In the sponge-center is a light source. The image illustrates the functionality of raytracing by computers and the resultating shadow position and orientation. The bottom touches on the Menger sponge. The light is slightly dimmed, so that the shadow effects take visual effect. A reflection at the verticle axis, going through the image center, offers, that the rendering is accurate, because symmetry is given.
<a href="//commons.wikimedia.org/wiki/User:PantheraLeo1359531" title="User:PantheraLeo1359531">PantheraLeo1359531</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>