I wish I could show everybody how this works! It's so cool! But not everyone can see this, including my mom 😭 You can call this stereogram or commonly known as Magic Eye. I found that the best technique is to bring the stereogram right up to your face and relax your eyes (you can even try crossing your eyes) then pull your phone away until you see the image turns into a 3d image.
I could see a horse, a log that it's jumping over, and a leafless tree in the background towards the right.