Around 1995 I wrote a DirectDraw text-editor that would render two images and force you to defocus your eyes like the op-art-3d puzzles: making the viewer have

Around 1995 I wrote a DirectDraw text-editor that would render two images and force you to defocus your eyes like the op-art-3d puzzles: making the viewer have to focus far away. It worked for images but not for reading small text.