Here we go again with the latest head scratcher brainy boffins have devised to test your intellect.
They reckon that people who can solve the puzzle within 13 seconds have a high IQ. So what better way to test your own grey matter during a break from work?
The teaser is the latest in a series to get the cogs turning. The puzzles are billed as a great way of challenging cognitive skills, problem solving abilities and helping folk focus.
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The Mirror reports how they are also a tried and tested way of improving your mood and providing your brain with a much-needed boost. JagranJosh has recently shared a tricky brain teaser that challenges you to try to identify a hidden letter among the X's and K's.
Does that sound easy? Well, there's a time limit, and according to the website, only people with high IQ can spot the hidden letter within 13 seconds.
In the brain teaser, there are five rows of X's and K's, and you'll need to scan all the rows and columns quickly to be able to find the answer
Can you find the odd letter within the time limit? If you need help, you can see the answer below – but stop scrolling unless you want spoilers.
Other similar brain teasers doing the rounds of late include trying to spot the odd cat in a tricky puzzle within seven seconds. Or try to trying find the correctly spelled word in a list of wrong ones.
Or you could challenge yourself to find the panda among the humans in this puzzle within seven seconds.
Another puzzle challenges you to spot five specific items within an image of three people and a dog. If you can find them within 15 seconds you're deemed a 'genius'.
Alternatively, you could try and find out your worst personality traits with an optical illusion.
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