Pyramid on top, or Hollow Tube Illusion
This is a fun little optical illusion that is a solid cement column. The photographer said it was taken in Germany. What appears at first to be a tall column that is hollow in the center, is actually something else, it is a solid cement column that has a pyramid shaped piece on top. The photographer was smart in that they looked for the exact angle to make the picture interesting.
This is a key point that doesn’t just have to be taken into account in optical illuions. Any picture you take, chances are, there is a better angle to take the picture that will make it more interesting. Taking a picture of a kid — get down to their level, or better yet, pointing up so you are looking up at their face.
Back to the illusion - Love it. Credit for the optical illusion photograph to http://prashusite.googlepages.com