As if I didn't know?
Areceibo, the Vogager project, SETI...they are all looking for life in the universe and therefore should be in a discussion under Space. I can't see how you can look at the faces and binary codes and even the huge three dimensional alien face and say these were man made.
The crop circles that HAVE been made by paid croppies are not that exacting or three dimensional; nor are they that huge. But it's easier to say "no" first, (can't be) rather than look at all the details and say "maybe, let's look further or follow this"....or better yet, WTF?