
If you cross fuse the top images (or divergently fuse the bottom), the figure appears as a black object visible through two holes and a serrated contour running along the right side (diagramed in the top right figure below). When the bottom to images are cross fused (or top two divergently fused), observers report the appearance of 6 black discs visible behind an irregularly shaped, white occluding surface (diagramed in the top left figure below). The two images presented to the two eyes are identical in both images; the only difference is that the images have been interchanged in the two eyes, inverting the disparity relationships. Note that the shape of the completed contours in the two depth configurations is very different (6 black discs in the amodal (or occluded) case, but only two completed holes and one serrated edge in the modal case). This has a large impact on theories of contour completion, particularly those that predict that the shapes of the completed contours should be the same in these two cases. A paper on this topic can be downloaded here.
