I'm pretty sure it is just an illusion of shadows that make it look like a 3D object on the moon. Like
Julian Beever's
3D art.
I made an image to help show the illusion for what it is.
If you look at the craters in image A and B you can get a good idea of the direciton of the Sun based on the shadows and highlights. If you look at
the supposed "moon hut / box illusion" and it's "shadow illusion" in image C, you can see the direction of the Sun would have to be from a totaly
different direction in order to create the "shadow illusion". So the extreme difference in shadow angles tells me that the "moon hut" is just an
illusion. It is NOT a box with a shadow.
I believe it is just a high ridge creating a shadow. If you look at image D, I highlighted the highest ridge points in thick RED. The thin red lines
are representing the slope/incline up to the ridge top. If you compare the shape of the ridge top, with the shape of the shadow, you can see a near
identical shape.
This means the illusion is just a ridge top that is creating a shadow with an identical profile.
So, there really is nothing there.
[edit on 13-10-2009 by ALLis0NE]