Conic sections
<a href="//commons.wikimedia.org/w/index.php?title=User:Laurens&amp;action=edit&amp;redlink=1" class="new" title="User:Laurens (page does not exist)">User:Laurens</a>
CC BY-SA 3.0
Semi-vector version of <a class="external free" href="https://en.wikipedia.org/wiki/Image:Conic_sections_3.png">http://en.wikipedia.org/wiki/Image:Conic_sections_3.png</a> by <a class="external free" href="https://en.wikipedia.org/wiki/User:Duk">http://en.wikipedia.org/wiki/User:Duk</a>