Only those with great vision can find ducks lurking in pebbly optical illusion

Want to wake your brain up?

If you're feeling a little sluggish, it could be a good idea to partake in a puzzle. It'll get you feeling alert in no time – as you'll need to solve it fast.

The brainteaser, which was posted onto Reddit, asks you to spot the duck toy in the image in less than 13 seconds. It sounds easy enough, but it'll drive you quackers as the bird is totally transparent.

To make things worse, it's camouflaged within a pebbly backdrop. There are countless stones that provide the perfect hiding place for the kids' toy.

The baffling picture left people completely stumped, with some complaining it was too tricky to complete. One user asked: "There's witchcraft afoot in how well that was hidden!"

To make the challenge less daunting, you can divide the photo into sections and carefully comb through them. Casting your eyes from left and right in a methodical way should help you to locate the duck in question.

If you need more help, focus your attention onto the left hand side of the image. And if you're still struggling, the answer is below.

Putting people out of their misery, one Redditor revealed: "I found it. It's a tiny translucent glass duck directly in the middle of the left side of the image. Find the cracked twig that sort of looks like a clothespin and follow it down in a straight line slowly and you'll see it. You're welcome, hope it helped."

Brainteasers can be good for you in several ways. Just like physical exercise helps maintain your body, they can provide a form of mental exercise.

They challenge your brain to think in new ways, which can improve cognitive functions. Research also shows they can sharpen your problem solving abilities.

They often require plenty of logic, pattern recognition and critical thinking skills. So the more you do them, the better you may get at these skills.