The human brain is fascinating. It can process complex calculations and craft the most amazing creations that even the world’s most powerful computers cannot even fathom. Simply put, there’s little we can’t do when we put our minds to it.

That said, optical illusions are designed to overwhelm the brain and stop it in its tracks. When you see artist Bev Doolittle’s piece, “The Forest Has Eyes,” you’ll think you’re looking at an illustration of a man guiding two horses through the woods. But take a closer look… and get ready for a mental workout!

This optical illusion by Bev Doolittle, entitled “The Forest Has Eyes,” includes 13 hidden faces. How many can you find?

1-faces-illusionBev Doolittle

Did you find all 13 faces? Here they are…

2-faces-illusionBev Doolittle

Some of them are much easier to locate than others. They’re particularly tough once you look at the background where the trees begin to blend in. How many faces did you find?

Share this illusion—and try to stump your friends—below!