Illustration of Neighborhood (mathematics)
<ul><li>Conversion to svg: <a href="//commons.wikimedia.org/wiki/User:CheCheDaWaff" class="mw-redirect" title="User:CheCheDaWaff">CheCheDaWaff</a></li>
<li>Original: <a href="//commons.wikimedia.org/wiki/User:Oleg_Alexandrov" title="User:Oleg Alexandrov">Oleg Alexandrov</a></li></ul>
<span class="int-own-work" lang="en">Own work</span>