A researcher in <a href="https://en.wikipedia.org/wiki/control_theory" class="extiw" title="en:control theory">control theory</a> showing a child a device with <a href="https://en.wikipedia.org/wiki/propeller" class="extiw" title="en:propeller">propellers</a> (open doors for popular science at <a href="https://fr.wikipedia.org/wiki/LAAS-CNRS" class="extiw" title="fr:LAAS-CNRS">LAAS-CNRS</a> in Toulouse, France).
<a href="//commons.wikimedia.org/wiki/User:Guillom" title="User:Guillom">Guillaume Paumier</a> (user:guillom)
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>