This is an optical illusion, what's the first thing you see?

I see two faces looking at each other when I first looked.
Can read about it and watch a video here...
This is an optical illusion, what's the first thing you see?

I see two faces looking at each other when I first looked.
Can read about it and watch a video here...
I saw the left-hand face first, then the right-hand face and lastly the glass. Now I know that they are there, I can flip between faces and glass with ease. I can draw portraits with a fair degree of accuracy and I think that I am wired to notice faces preferentially.
I saw the left-hand face first, then the right-hand face and lastly the glass. Now I know that they are there, I can flip between faces and glass with ease. I can draw portraits with a fair degree of accuracy and I think that I am wired to notice faces preferentially.