These images were created by viewing a sinewave grating through diamond apertures. Relative disparity was added by shifting the grating relative to the aperture boundaries to create a disparity difference between the grating and the aperture boundaries. If the two columns on the left are cross-fused (or right two images are divergently fused), a dramatic illusion can be experienced. In the top image, the figure appears as a white diamond on a black background visible through fuzzy black bars. In the middle figure, the same grating appears as a black diamond on a white background visible through fuzzy white bars. In the bottom figure, a very unpleasant and unstable figure appears. The only difference between these images is the lightness of the background; the central figures (gratings) are physically identical. When the disparity relationships are inverted, the grating simply appears as a surface visible through diamond shaped apertures. The first paper on these phenomena can be downloaded here, and a comprehensive theory of these and related stereo phenomena can be downloaded here.