Earlier this year my daughter Indigo came across an interesting example showing how one color can be extremely affected by another color, she created this series of images to illustrate this particular phenomenon.
In the image above, it appears that the eye on the left is blue, matching the blue circle on the upper right, and the eye on the right is gray. Believe it or not, both eyes are the same gray!
In the image below, cover the gray side of the image with your hand and watch the half of the eye on the red field turn blue to match the blue circle on the right.
If you are interested in learning more about how colors interact and how to make them work for you, my online Color Theory class is on sale during the month of September for $45.