Cyan Link is the input rotating regularly.
<p>Pink Link is the output which dwells in one position.
</p><p>Orange circle indicates the circular arc the coupler curve is approximating.
</p>
Made with GeoGebra.
<a href="//commons.wikimedia.org/wiki/User:Arglin_Kampling" title="User:Arglin Kampling">Arglin Kampling</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>