A schematic of a general queue system
<ul><li><a href="//commons.wikimedia.org/wiki/File:Queue_System.PNG" title="File:Queue System.PNG">File:Queue System.PNG</a>: <a href="//commons.wikimedia.org/w/index.php?title=User:AdamD&amp;action=edit&amp;redlink=1" class="new" title="User:AdamD (page does not exist)">AdamD</a> / * derivative work <a href="//commons.wikimedia.org/wiki/User:Begoon" title="User:Begoon">Begoon</a></li></ul>
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