Illusion test your eyesight with 16 hidden faces how many you spot

THIS mind-bending optical illusion will certainly test your eyesight - and your patience.

Hidden in this historical brain teaser titled The Puzzled Fox are 16 animal and human faces - but how many can you spot? 

The sweet woodland scene shows the cunning animal appearing to climb a tree as three eagle-eyed birds watch on.

But camouflaged among the greenery, 12 other pairs of eyes are secretly staring back at you.

Fear not if you struggle to spot any - as the brain teaser has been puzzling illusion lovers since US printmakers Currier and Ives produced it in 1872.

Now nearly 150 years on, The Puzzled Fox has reared its perplexing head again to challenge a fresh audience. 

The fox is surrounded by other animals - including a horse, lamb and a now-extinct passenger pigeon.

The fox is surrounded by other animals - including a horse, lamb and a now-extinct passenger pigeon.