3D rendering of a passive structural control building element called Earthquake-Protective Building Buffer
<a href="//commons.wikimedia.org/wiki/User:Shustov" title="User:Shustov">Shustov</a>
CC BY-SA 3.0
Own work by uploader, see <a rel="nofollow" class="external free" href="http://www.ecs.csun.edu/~shustov/CME-C5.htm">http://www.ecs.csun.edu/~shustov/CME-C5.htm</a>