Think you’ve got the eyes of a sniper? Spot the 13 hidden faces in under 7 seconds to prove you’ve got 20/20 vision

ONLY the most eagle-eyed will be able to spot the 13 hidden faces in this devilishly difficult optical illusion.

Put your vision to the test with this tricky brainteaser, which will have you staring at your screen trying to figure it out.

Whether you’re trying to improve your sight, or test your IQ, this puzzle will prove a challenge to many readers.

Put your observation skills...