<a href="https://en.wikipedia.org/wiki/Perspective_correction_lens" class="extiw" title="w:Perspective correction lens">Perspective correction lens</a><br>curtagon
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/sarchi/">Peter Harris</a> from Maidstone Kent, UK
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/sarchi/103180428/">Flickr</a>