Leave it to a person skilled at both magic and balloon twisting to come up with an illusion so crazy it is hard to accept. This is even after testing the lines to be perfectly straight with a ruler, a level, and Adobe Photoshop about ten times. The human mind is an interesting thing. The first thing I thought of was the repetitive task of straightening horizon lines in photos and how often they don't look quite right. Now I think it is time to stop trying since my eyes and mind can be this badly fooled.
Martin S. Taylor, a hypnotist from the United Kingdom, tweeted this mind-boggling illusion with the simple challenge included right in the photo. The illusion itself is not new. It is called the "café wall illusion" and happens due to a phenomenon called irradiation. This is the visually apparent extension of the edges of a brightly illuminated object against a dark background.
This well executed version of the illusion made by Victoria Skye really pushed the effect into overdrive. Skye is a professional illusion artist living in Atlanta, Georgia. Her favorite pastime is actually tricking the brain. Making the impossible possible sounds a bit like an Elon Musk motto. But Skye appears to do it quite often on a much cheaper budget. She even creates physical illusions called, "impossible objects," that are collected by magicians and puzzle enthusiasts around the world.
Skye went on to tell me that the original version of this illusion made famous by Richard Gregory was from a real brick wall of a cafe in Bristol, England. She was able to mix some of the basic techniques used in that illusion with some variations made by a experimental psychologist in Japan named Akiyoshi Kitaoka.
Skye also shared that her research into this particular illusion led her to ask illusion neuroscientists and coauthors of multiple books on illusions Stephen Macknik and Susana Martinez-Conde about the effect. They told her this class of illusions is called the "twisted cord" because the first version, observed by Scottish physician, was in the form of a twisted cord. You can find a number of examples on Google Images.
Check out how the illusion quickly disappears when the contrasting brightness is taken away and only the pattern remains:
The next time you have trouble getting the horizon straight in your photo, you can always try and blame the darn irradiation! I know it is going to be hard to trust my eyes for a while, now.
Illusion used with permission by Victoria Skye.