If your job requires you to stare at a computer all day, your eyes may get pretty tired by the afternoon. One way to wake up your senses is to force yourself to look at something in a new way. The image below looks like a spiral pattern at first glance, but if you examine it closely you’ll find two words hiding in plain sight.
This trippy optical illusion comes from Rainbow Riches Casino. They showed 80 people the picture, and less than half of them were able to spot the secret message.
If you’re bringing the screen closer to your face to look for tiny words tucked among the stripes and swirls, you’re taking the wrong approach. The words are actually big enough to stretch across the square. You can try finding them by leaning away from your device and letting your vision unfocus. If a minute has passed and all you’ve gained is a headache, you can find the answer by reading on to the next paragraph.
This illusion takes advantage of the confusing pattern to trick your brain. The words FREE and SPIN appear in text that matches the design, but in a slightly lighter shade. Because the spiraling stripes are leading your eyes different ways, it can be easy to brush over the minute color differences and miss the message altogether.
Stripes can change our perception of how light or dark a shape beneath them is. This is because the shape takes priority in our perception and our brain assimilates the color into its surroundings even if it’s subtly different. For an example of this effect, check out this mind-bending eye color optical illusion.