A tricky brain challenge is putting people's cognitive abilities to the test, and you'll need to harness all your perceptive powers in order to crack it.
The puzzle in question shows row after row of the number 964 duplicated over and over again, with a solitary 994 hidden amid the sea of identical figures.
If you manage to spot the lone 994 in 10 seconds or under, then you're likely to be among the top two per cent of those with a high IQ, and will probably have extraordinary ninja skills to boot.
Ready to give it a go for yourself? Set your timer and take a look at the following dizzying image:
The tricky brain teaser, which was originally shared by Fresherslive, is intended as a puzzle for all age groups, but it's a particularly challenging one.
The human brain is very adept when it comes to recognising patterns, and our minds will work at a rapid pace to create a "whole" image from different fragments.
It can therefore be difficult to pick out a difference within an otherwise uniform picture, with our brains working hard to fill in the gaps.
With this particular optical illusion, you'll need to really concentrate, scanning each section individually, while not letting yourself get distracted by the false complete image your brain will have constructed.
Ready to give it another go? Read on to see the same image again, this time with the number in question circled.
Did you manage to spot it? Don't worry if not. Like all things worth trying in life, practice makes perfect when it comes to becoming a puzzle master.
In the meantime, why not give the classic "Find the Flower Girl" brainteaser a try? This vintage illusion has challenged generations of puzzle lovers to find a girl's face hidden among rose petals in 20 seconds or less.
Do you have a puzzle-related story to share? Email us at julia.banim@reachplc.com
