These photos use the cross eye method. Here is one of countless websites that explain the process:
https://www.3dphoto.net/text/viewing/technique.htmlAnother explanation: http://www.vision3d.com/3views.html
I also have a few older examples in this folder:
http://karin.zenfolio.com/p569446173 Some people take quite a while to get it, but please don't give up! The effect is startling and delightful - the 3D makes it so much more exciting!
Once you see your first one, it gets a little easier every time. After some practice, you'll be able to see them easily within one or two seconds.
