The Spinning Girl: You Won’t Believe Your Eyes
This is pretty incredible. In the comments to the FedEx post, Silas linked to this silhouette of a spinning girl. When I first looked at it, I would have bet $100 that it was “clearly” spinning in one direction. I sat and stared for a several seconds, and thought, “There is no way I could possibly ‘see’ this girl spinning the other direction.”
And yet, I followed the instructions and focused on a small part (in my case, I watched where her foot bounced up and down on her shadow). And then all of a sudden she was “clearly” spinning the opposite way, and I would have bet $100 that that was the only way to make sense of it.
The effect is so strong–in contrast to the Necker cube–that I am still suspicious that the website randomly changes her direction every few minutes. I.e. I still can’t believe that the same sequence of two-dimensional images gives the illusion of spinning in one direction or the other.
