Optical illusion triggers debate about hidden number inside circle

This optical illusion has gone viral once again because it has left netizens divided over a number it hides at the centre., Viral News, Times Now

Optical illusion red dot sight test with a hidden image leaves the internet baffled

Incognito: The Secret Lives of the Brain: Eagleman, David: 9780307389923: : Books

Mind-boggling optical illusion with black and white circle shows a hidden number – and everyone is seeing it differently

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What number do YOU see? Optical illusion goes viral

Optical illusion red dot sight test with a hidden image leaves the internet baffled

An Optical Illusion Where Circles Seemingly Move Out Of Place Has Become An Internet Sensation

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Frontiers Split-Second Unlearning: Developing a Theory of Psychophysiological Dis-ease