A <a href="https://en.wikipedia.org/wiki/theremin" class="extiw" title="en:theremin">en:theremin</a> exhibited at the <a href="https://en.wikipedia.org/wiki/Exploratorium" class="extiw" title="en:Exploratorium">en:Exploratorium</a> in San Francisco
<a href="//commons.wikimedia.org/wiki/User:Wctaiwan" title="User:Wctaiwan">wctaiwan</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>