Okay, why, exactly, is the hypothesis that it's humans so good that no other hypothesis is worth bothering with, even though we only have a few people claiming responsibility for a few hundred crop circles out of thousands, plus demos of how easy it is? What's the principle or breakdown here? The things I wonder are like, does every group invent it from first principles, or do they pass it on from group to group? Has anybody studied them like you would crime scenes, looking for patterns of scuff marks, bits of paint, urine spots, wood splinters, etc? Anyway, here's an interesting (though credulous) article that includes a few construction details: http://science.howstuffworks.com/crop-circle.htm It doesn't mention that ropes can be used as rulers as well as compasses. Maybe flashlights pointing up into the sky make good location markers. It does mention one related flow of money, not that I think that's an important factor. Some favorite quotes: "Astronomer and former Boston University professor Gerald S. Hawkins studied several crop circles and found that the positions of the circles, triangles and other shapes were placed based on specific numerical relationships. In one crop circle that had an outer and an inner circle, the area of the outer circle was exactly four times that of the inner circle. The specific placement of the shapes indicates that, whoever the circlemakers are, they have an intricate knowledge of Euclidean geometry (the geometry of a flat surface introduced by the mathematician Euclid of Alexandria)." They know of Ratios! And Geometry! And the ancient art of Making One Circle Twice As Wide As Another, thought to be lost since the days of Pythagoras!! 'This formation was discovered in Eastfield, England, in June 2004. An article in the Western Daily Press called the design "uncannily similar to plans for one of Nikola Tesla's early pieces of equipment."' (Someone must have--uncannily--copied a picture from a book.) Here's my favorite crop circle in the gallery of pictures for the article: http://science.howstuffworks.com/enlarge-image.htm?terms=crop+circles&galler... or http://tinyurl.com/5u2qhs --Steve