Like any organ of the body, the brain needs constant exercise, be it with puzzles or even some clever riddles. The eyes also require training in order to improve our attention to detail, and there’s nothing better than a test to challenge them.

Spotting the difference can be a frustrating exercise at the best of times, but this game is extra tough. The series of seemingly identical photos all contain a few subtle differences, and some are almost impossible to spot.

So Find the differences in this picture. Some people are so observant that they can easily tell the difference between an owl and a barn owl. And then, there’s the group of people that are so clueless that they couldn’t even distinguish a zebra among cows or a wild boar among pigs. But maybe, just maybe, it all comes down to exercising our deduction skills.