You’re not the only one. Here’s something else to entertain yourself for a few hours.
They’re called stereograms, and the easiest way to view the hidden 3D image is to start with your nose about one inch away from your screen and stare at it for a few seconds. Then slowly back away.
It can take a while to get the hang of it, but don’t give up! If you found these to be too easy, or you want to see some others, you can view more here.