This puzzle might not be as simple as it looks.

Brain teasers and other puzzles can do wonders for our cognitive function, as they help to reduce the risk of dementia and can improve the connection between your brain cells. What’s more, they’ve even been proven to boost your mood and reduce stress, thanks to the dopamine that’s released in your brain when you successfully solve one.

One puzzle, however, might not have the calming effect you’re looking for – as it’s actually left those who try…