The red-green blend cross-eye chart can be combined with with color fatigue to get a strange situation where the color fatigued portion of the visual image is doing a slightly different color reversal dance.
Go the typical cross-eye experiments at Probaway.wordpress.com for more experiments and help on how to cross your eyes to get the weird brain effects. In this experiment begin the experiment by sitting well back from the computer screen, say two arm lengths, and cross your eyes so the two black dots fuse into one image. It helps to rotate your head slightly around your nose to screen axis, which will make the two dots seem to dance up and down relative to one another. That helps to make them fuse, but once they do fuse hold your head still for ten to thirty seconds and watch your brain try and make sense of the conflicting images. There will be a dancing of colors across the whole field of the flag.
After a minute of that strange fun move your head directly toward the screen until you are as close as your eyes will let you get without losing your fused dot. That will be about one foot away. After you practice that for a few times you can start moving slowly back and forth from you distant position to your close one without losing your fuse. Once you can do that successfully, remember rocking you head slightly will help you maintain your fuse, you can proceed to the new experiment.
Go out to your distant position and stay fused on the dot for a while, thirty seconds or perhaps a minute will do. The purpose of this is to color fatigue your eyes to the colors reaching each eye independently. After that fatiguing time move toward your screen about half way. A color fatigued image will appear around the dot, but that image will be smaller than the new flag image in your eyes retnia, and so it will behave differently from the portion of the flag that is still outside of the color fatigued area.
I think this proves that the dancing of the colors is taking place within the visual centers of the brain and not in the eyes themselves. The color fatigue is in the eyes, but the color dancing is in the brain.
Enjoy yourself and tell me what you see.