Twin-cylinder double-action <a href="https://en.wikipedia.org/wiki/steam_engine" class="extiw" title="w:steam engine">steam engine</a> built in <a href="https://en.wikipedia.org/wiki/LEGO_Technic" class="extiw" title="w:LEGO Technic">LEGO Technic</a>. The machine works when vacuuming through both pipes.
<a href="//commons.wikimedia.org/wiki/User:Bernard_de_Go_Mars" title="User:Bernard de Go Mars">Bernard de Go Mars</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>