Apart from being fun, optical illusions also test our patience and stimulate our thinking. One of them is the photo that managed to confuse some.
If you can spot the secret number in this puzzle within seven seconds, you have very sharp eyesight and a high IQ. Many see a neon green circle, but only a few can decipher the illusion in seconds. Although it looks like a simple puzzle at first glance, there is a two-digit number hidden in…