Optical Illusion: Einstein or Harry Potter?

I saw this optical illusion at the MIT museum in Cambridge, at first I didn’t understand how it worked. Later as I walked to the end of the room, I saw that someone had switched the drawings!

As I walked closer, they magically reverted back to Albert Einstein.

A trick? Nah, it was just an illusion!

STEP 1: Eight Portraits
Here’s what you see what you’re far away, it looks like 8 different portraits!

Optical Illusion (see large image version to compare)

STEP 2: Watch as they magically turn to Einstein
Now, the expanded image (Yes, it’s the SAME image, just larger) changes as you get closer. It’s JUST Einstein. You can try, by expanding the image and stepping backward!

Click here to see the larger version of the same image

How did this work? When our eyes see the details when we get closer, it changes our perception of the image!

I shared this with many of my friends including my buddy Neil.

Update: From the comments, we should take time to credit Aude Oliva, Ph.D. who is the creator of this fine work. I had a great time visiting the MIT museum and encourage you to check it out too!