I accidentally photographed the Scintillating Grid Illusion. I was reviewing my photos and at first, I thought I had gone crazy.
You may not be able to see it here at this size, but if you look at the image at 1024 x 681, you'll see it. First take a look at the image by clicking on it below. Then follow the link at the end for another example. Oh, and I photographed this while riding across the Williamsburg Bridge on Sleipnir.
My friends tell me that this photo has a much stronger effect on me then on them. If you don't really see it flashing, check this out. this is what it looks like to me: Another example of the Scintillating Grid Illusion.