Optical illusions, like this one, are fun and good for the brain.

Find Dog’s Master in 7 Seconds
Look at this picture with a dog’s head. There’s a challenge to find the dog’s owner, and some people with “hunter’s eyes” can do it in 7 seconds.

In the picture, there’s more than just the dog’s head. The owner is hiding somewhere, and you have to find them in 7 seconds.