New Delhi, Oct. 7 -- Optical illusions are one of the most popular games on the internet now. Since these games are short and can improve our concentration, millions of people have developed a love for viral brain teasers like these. The latest optical illusion to catch the internet by storm asks players to find the number 15 among 51s. Can you do it within just 10 seconds?

At an initial glance, there is a grid of the number 51. For a casual observer, the number 51 appears to occupy every nook and cranny of the grid. However, if you are attentive and approach the photo carefully, the number 15, which is the reversal of 51, is somewhere subtly hidden. You have only 10 seconds to locate the number 15. Do you think you have the technique an...