[Citizen of the Savage Nation]

Hmmm, that was not so obvious to me. If you were going to do such a thing, how would you do it? I've seen the shots of admitted hoaxers doing their trade, but it always seems like their efforts result in circles that look like crap. What I haven't seen yet, is to have these guys do it real time, in front of witnesses, and produce something like #9.

[RightWhale]

that was not so obvious

A couple of things to look for:
An unsymmetric piece in the design that in a perfect mathematical graph wouldn't be quite like that
Crude patterns in the grass as laid down as opposed to what was left standing.

Been a draftsman for a long time. You get so you see the rough edges and don't worry so much about artistic content.

[balrog666]

Hmmm, that was not so obvious to me. If you were going to do such a thing, how would you do it? I've seen the shots of admitted hoaxers doing their trade, but it always seems like their efforts result in circles that look like crap. What I haven't seen yet, is to have these guys do it real time, in front of witnesses, and produce something like #9.

Why would you assume they would do it without planning it out first?

BTW, a simple Spirograph-type setup would produce #9.