http://www.dailymail.co.uk/femail/article-6113599/Is-beach-door-Infuriating-new-optical-illusion-leaves-web-baffled.html

https://i.dailymail.co.uk/i/newpix/2018/08/30/10/4F85F60300000578-6113599-image-m-2_1535621150780.jpg

90度回転させると
https://i.dailymail.co.uk/i/newpix/2018/08/30/10/4F85F61B00000578-6113599-image-a-9_1535621318449.jpg

正解はまだ発表されてないらしい