Radial Reciprocating Electric Motor
<a href="//commons.wikimedia.org/wiki/User:MichaelFrey" title="User:MichaelFrey">MichaelFrey</a>
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>, inspired by <a rel="nofollow" class="external free" href="https://www.youtube.com/watch?v=jeHNMjBrvLk">https://www.youtube.com/watch?v=jeHNMjBrvLk</a>