Contest solution

I guess it is high time to reveal the secret of the abstract photo from this post. Regine, you were very close, the picture shows a window. It was actually a row of keyhole shaped windows in the hall of African Mammals in American Museum of Natural History in New York. The tree like shape on the window comes from shades made from wicker, thus it might make you think of a tree.
Here is another view of the windows. I was photographing from dark inside of the room to the bright midday outside, thus the windows are only silhouettes, blurred in corners by Lensbaby (right again, Regine!).
Next post is number 400. Who would think….