New Delhi, June 30 -- Optical illusions have a way of making our brain work overtime. A viral challenge is putting eyes and attention spans to the test. At first glance, the image is packed with the number 4502, repeated in a grid. But look closer - somewhere in this sea of 4502s is the odd one out: 4052.

Let us explore why it is not as simple as it sounds.

The illusion plays with uniformity. All digits are in the same font, size and alignment. Our brains tend to scan patterns quickly and assume repetition. So, spotting the one different number becomes a visual challenge. You are not just looking, you are decoding.

The number 4052 is cleverly hidden in the image's 10th row from the top and 8th column from the right. The difference betw...