The purpose of this image is to perceive a 3D effect by feeding each eye a different, matching image. In order to make that happen the viewer needs to cross his eyes. If all goes well and you are able to fuse the two images you will see a combination of both images, meaning you will see open space on BOTH sides of the mountain. Possibly you will also perceive a 3D effect. I don’t see it yet so I’m not really sure… I can cross my eyes and make it fit, but it is pretty blurred and the combination of both pictures isn’t very stable because I tend to suppress parts of what the left eye is seeing. So it isn’t fixed and things tend to jump around. Those problems are exactly the reason why I think it’s a great exercise and at this point it is something I can start considering without getting way ahead of myself and get totally frustrated. For me it is a pretty intense exercise but if done relaxed and well rested it is not too demanding, so I will keep at it. A fellow strabismic told me he had a stereo break through while practicing this kind of images, so who knows! To find more of them, Google ‘cross-eyed 3D photography’.