Illustration of <a href="https://en.wikipedia.org/wiki/Cauchy_sequence" class="extiw" title="w:Cauchy sequence">Cauchy sequence</a>
<a href="//commons.wikimedia.org/wiki/User:Oleg_Alexandrov" title="User:Oleg Alexandrov">Oleg Alexandrov</a>
self-made, with <a href="https://en.wikipedia.org/wiki/matlab" class="extiw" title="w:matlab">matlab</a>