Comment by the__alchemist

If you've done Magic Eyes, this is straightforward. Was able to get all 3 of the test images quickly.

This is with focusing beyond the screen. Focusing in front of the screen is something I am unable to do, and not for want of effort.

Also, your eyes might accidentally do this if looking at tiled patterns, e.g. wallpaper.

Relative image size (e.g. view distance) is important.