Can you spot the master? Photo/Puzzle: PlayBuzz.com
There is a new optical illusion sweeping the web - and it could well be the toughest yet.
Hidden in the vintage illustration of a dog is the head of his master - but can you spot him?
The image, posted by Playbuzz, dates back to the turn of the century and was the face of a trade card used as an early advertising gimmick.
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If you look closely, you can spot the dog's owner in the middle of the picture - with Spot's ear acting as his hat.
On the side of his cheek you might be able to make out his eyes, nose and mouth - but you'll have to tilt your head to spot it.
People took to the comments section of the Playbuzz website to comment on the difficulty of spotting the dog straight away, with one saying that they're usually good at optical illusions but struggled with this one.
Others, however, said it only took them a couple of seconds - so how did you do?
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