India, Aug. 26 -- A new optical illusion is putting people's eyesight - and patience - to the test. The challenge looks simple at first glance: a full grid of the number 349 repeated over and over. But hidden somewhere inside the pattern is one cell that does not match the rest. The puzzle has been circulating across social media feeds, with many users admitting they needed far more than a quick scan to spot the odd one out. At first, the grid looks almost hypnotic, with neat rows and columns blurring together. That is what makes it so tricky.

Take a look at the image below:

Our eyes naturally skim patterns. When every cell shows the same three digits, the mind quickly assumes uniformity and stops checking closely. Psychologists say thi...