I think one quality that optical art must have is its ability to excite eyes. Our brain responds to the visual information it presents resulting in viewers to feel various sensations as if it is reacting to various drugs. I am sure different image trigger different chemical in our brain, creating different mood.
For that reason we use images to aid in our meditation to induce this feeling of euphoria.
Just by staring into this picture, I feel dizzy. Don't you?
This is a different interpretation of Yin Yang or 69.
