The structure of the Blowfish cipher.
Benjamin D. Esham (<a href="//commons.wikimedia.org/wiki/User:Bdesham" title="User:Bdesham">bdesham</a>)
Own work  by <a href="//commons.wikimedia.org/wiki/User:Bdesham" title="User:Bdesham">bdesham</a> using:  <a href="https://en.wikipedia.org/wiki/Inkscape" class="extiw" title="w:Inkscape">Inkscape</a>