Colors

I think it is so amazing how colors behave in our bodies. If you happen to have a bruise you can watch how its colors change... and always move around the spectrum. At first it will be red or red purple. Then it will change to a purple blue, then green, then yellow, and then browinsh (though not orange, pretty close). Similarly, when we see an after image with our eyes closed, we can always expect it to change color as well, and always moving from one to the next around the color circle! I wonder if there is any other similar manifestation of color in the body.