India, June 17 -- Optical illusions are a great idea if you want to give your brain a workout. These illusions invite you to look at a puzzle and figure out if things are truly what they seem. More often than not, your eyes trick you into perceiving shapes or words that might not be there. This optical illusion going viral on Reddit is surely a puzzle that can only be solved by the sharpest minds. Known as the Coffer Illusion, the challenge has stumped many people.

The illusion features a series of grey rectangular panels. That's all you see at first glance, right? The challenge is to find 16 circles in the image. Confused? The answer is right in front of your eyes-literally.

The rectangular panels may seem to be the only thing dominati...