When we see things, we typically see one image which appears to have depth (if we have two functional eyes of course). I understand this is because the images from each eye are matched, and the slightly different perspective caused by the horizontal displacement of the eyes is used to generate the perception of depth. It seems that when images from both eyes do not match, some kind of contention process causes the separate images to alternate in conscious perception (binocular rivalry). That seems clear enough. If however I deliberately cross my eyes, I now see two distinct representations of the scene, for example, a cube on my desk can be made to appear as two distinct cubes. These remain within perception without alternating which shows that the binocular process must still be able to match both images (although I can with a little effort cause one or the other, or both, to fade from perception, but that does require effort - typically, both are distinctly visible). But what on earth is going on that I see two images? There is after all no "screen" in my head against which the images are "projected". I can understand that a single conscious scene is generated perceptually via some sort of fusing of the two images. But what are the mechanics behind disassociating the fused image?