Lenticular cloud and zebra. (Photo by National Geographic)

Philadelphia Phillies Ben Francisco reacts after being hit in the head with a pitch by Cincinnati Reds Logan Ondrusek during the MLB National League Division Series baseball playoffs in Philadelphia, Pennsylvania, United States in this October 8, 2010 file photo. (Photo by Tim Shaffer/Reuters)

Ukrainian artist Oleg Shuplyak masters the optical illusion in his incredible scenic oil paintings.

A model presents a creation by French designer Alexandre Vauthier as part of his Haute Couture Fall/Winter 2016/2017 collection in Paris, France, July 5, 2016. (Photo by Gonzalo Fuentes/Reuters)

A model falls and gets help back to her feet during the fashion show for the Givenchy Spring 2016 collection at Fashion Week on, Friday, September 11, 2015, in New York. (Photo by Bebeto Matthews/AP Photo)

A model wears a creation by Peruvian designer Jessica Butrich during Lima Fashion Week, LIF Week Summer 15-16 in Lima October 28, 2015. (Photo by Mariana Bazo/Reuters)

A model walks the runway during the Versace show as part of Paris Fashion Week Haute Couture Spring/Summer 2015 on January 25, 2015 in Paris, France. (Photo by Pascal Le Segretain/Getty Images)