Diagram of tension forces on a curved surface.
<a href="//commons.wikimedia.org/wiki/User:Karlhahn" title="User:Karlhahn">Karl Hahn</a>
16 October 2006 (original upload date)
<a class="external free" href="https://en.wikipedia.org/wiki/File:CurvedSurfaceTension.gif">https://en.wikipedia.org/wiki/File:CurvedSurfaceTension.gif</a>