figure illustrating the definition of the second fundamental form of an embedded surface
<a href="https://en.wikipedia.org/wiki/User:Mathsci" class="extiw" title="en:User:Mathsci">Mathsci</a> (<a href="https://en.wikipedia.org/wiki/User_talk:Mathsci" class="extiw" title="en:User talk:Mathsci">talk</a>)
2008-07-26
I created this work entirely by myself using xfig in kubuntu