If you see the picture exactly as it is, you are using the left side of your brain. When you stare, you will see the figure shift and you will see the side of the face. Now you are using your intuitive right brain. You can switch back and forth between a frontal image and a side image.
Staring gets into the right brain (it sort of trances you out or puts you in an altered NON THINKING state). Begin thinking and reasoning about it and you will move back out of the altered state into Left brain thinking.
Now stare at this picture for a while….do you see this man turn his face and look toward the left? Do you see the shift in the eyes to the left? It did happen to me once, but when I tried it again it did not work. Is my thinking interfering with me seeing it again? Let us know your experience.