Black outlined <a href="https://en.wikipedia.org/wiki/Archimedean_spiral" class="extiw" title="en:Archimedean spiral">Archimedean spiral</a> with 8 revolutions on transparent background. The curve is smooth but interpolation is not very precise.
<a href="//commons.wikimedia.org/wiki/User:Incnis_Mrsi" title="User:Incnis Mrsi">Incnis Mrsi</a>
2010-04-27
<span class="int-own-work" lang="en">Own work</span>