<a href="https://en.wikipedia.org/wiki/Necker_cube" class="extiw" title="w:Necker cube">Necker cube</a>
<a href="//commons.wikimedia.org/wiki/User:Sarang" class="mw-redirect" title="User:Sarang">Sarang</a>
Own work based on: <a href="//commons.wikimedia.org/wiki/File:Cube1.svg" title="File:Cube1.svg">Cube1.svg</a>