A mind-boggling optical illusion composed of countless letters is perplexing internet users around the world.

Test your detective skills with this brain teaser from JarganJosh.com! Find the hidden letters among nine rows and 31 columns of letter Xs. How quickly can you solve it?

[Warning – spoilers lie ahead!]

“You need to think a little differently for coming on to the solution as the answer won’t be right in front of you. So, we have come up with an interesting brain teaser where you have to spot 6 hidden Ys among the group,” as the website indicates.

“An alert mind can identify 6 Ys within 13 seconds … This brain teaser is just another fun way to test your IQ.”

How quickly can you spot all the hidden Ys? Challenge yourself and time your performance: ready, set, go!

The Ys have been arranged in individual rows, and none of the Ys can be found inside the middle third of their sequence.

“Some puzzles don’t necessarily require mathematics skills or lateral thinking but are a simple test of your observation skills,” the website read.

“This riddle was tricky but simple as it needs less time and brain power to solve. But it sure feels great when you figure out the answer in a few seconds.”