An optical illusion is a visual phenomenon where the brain perceives an image differently from how it physically exists.

These illusions occur due to the way our eyes and brain process light, colour, patterns, and depth.

They often trick the brain into seeing motion, distortions, or hidden images that aren’t actually present.

In one such tricky brainteaser by optics4kids.org, readers are challenged to find the number of triangles in the picture below.

The image consists of three black circles,…