Drawing of typical combination gun or zwilling (top), drilling (middle), and vierling (bottom) layouts.
<div style="display:inline-block;padding:0 3px;background-color:#CCF">Original:</div> <div style="display:inline-block;padding:3px 0;"><a href="https://en.wikipedia.org/wiki/User:Fluzwup" class="extiw" title="en:User:Fluzwup">Fluzwup</a></div> <div style="display:inline-block;padding:0 3px;background-color:#CCF">Vector: </div> <div style="display:inline-block;"><a href="//commons.wikimedia.org/wiki/User:Sarang" class="mw-redirect" title="User:Sarang">Sarang</a></div>
Own work based on: <a href="//commons.wikimedia.org/wiki/File:Combination_guns.jpg" title="File:Combination guns.jpg">Combination guns.jpg</a>