- Corrugated venus collected in 2011 on the Belgian part of the North Sea. <br><p>Width = 35 mm<br></p> <a href="https://en.wikipedia.org/wiki/Focus_stacking" class="extiw" title="en:Focus stacking">Focus stacking</a> of 11 pictures. © Hans Hillewaert - CC BY-SA 3.0 - Wikimedia Commons