A new optical illusion is putting people’s eyesight - and patience - to the test. The challenge looks simple at first glance: a full grid of the number 349 repeated over and over. But hidden somewhere ...

The trick here is that your eyes get used to the pattern right away. Once the brain sees row after row of the same figure, it stops searching for anything unusual. That is why the odd number blends in ...

Spot the hidden number of Ms: An optical illusion changes or confuses when you see within seconds, which is tricky and challenging too. It will be interesting, but it will make you scratch your head.