A new viral optical illusion will test the sharpness of your eyes and only those with the sharpest will be able to solve the hidden mystery within. Optical illusions can be a fun way to test the proficiency and speed of our brain, eyes and other sensory aspects of ourselves. A new and intriguing viral optical illusion challenges users to detect the number hidden within an image and it is leaving some people baffled. The image was shared on Twitter by @TheFigen_ who captioned the image: “Eye test! What number do you see?” The picture appears to show a blank square of red speckles, but if your eyes are sharp enough you may just about see a three-digit number hidden amongst the red speckles. Over 568,000 people have viewed the image and in the comments, people have commented on the number that they believe they can see. Sign up to our free Indy100 weekly newsletter For those with sharp eyes, the number can be seen going across the centre of the image, blending almost seamlessly in with the background until you spot it. In the comments, one three-digit number appeared very frequently, while the answers some people gave were less unanimous. One person guessed “572”. A few posed “573” while someone else said “285”. The answer was actually “571”, with most of those commenting giving the correct answer to the challenge. Other optical illusions that have taken the internet by storm include the viral “fourth object” trend on TikTok that challenges people to locate four different objects in one image. Have your say in our news democracy. Click the upvote icon at the top of the page to help raise this article through the indy100 rankings.