Amazing!
Ever since I was little, I have learned to love looking at optical illusions and impossible figures. In fact, before this came up, I was just looking up the Droste effect. It is great to see these illusions, but it would have been nicer if there had been a little sound. It would have also been better if it was not just that one picture in which you could identify the hidden picture. I think the hardest one was 15. I have actually seen some of these before as I have gone out and looked at these things.