This is one of the most common types of crop circles, with many variations. The same image is associated with the story in John 21, of the 153 Fish in the Net.

Tiphareth is in the centre of the Tree, and corresponds to the heart chakra level. It is the green flower here:

[Link: http://www.greatdreams.com/crop/chksys/chksys.htm ]

Dreams and certain crop circles seem to indicate a potential or future change in the sixth sphere of the Tree. The Seed of Life flower will open like the aperture of a camera, giving a twelve fold flower or design, with a six fold figure in the centre, such as a Star of David. This is similar to the traditional symbol of the heart chakra. The change, therefore, seems to indicate the opening of the heart chakra.

The "Da Vinci Code" crop formation seems to have the checkerboard grid on the floor rather than on the ceiling. It appears to be a 7 x 7 grid, rather than the 6 x 6. In terms of the spheres of the Tree of Life, this would correspond to Venus and the Magic Square of Seven. In this case, there are 49 numbers, and the total is 1225. Each row, diagonal, and column adds to 175.

Perhaps this is suggestive of the feminine aspect and thereby corresponds to Mary Magdalene. There may be a duality indicated in the sense of "as above, so below" corresponding to the Sacred Marriage of the masculine Bridegroom and feminine Bride.

A seven Fold Koch Fractal appeared around 9 August 1998, at Tawsmead Copse, near West Stowell, Wiltshire. It had 175 little circles, perhaps suggesting the Magic Square of Venus.

[Link: http://www.lucypringle.co.uk/photos/1998/uk1998di.shtml ]

Significantly, Venus is a primary factor in the Mayan Calendar, which ends on December 21, 2012, at 11:11 AM Universal time. Jesus and the Central American, Quetzalcoatl, are associated with the Morning Star, Venus.

I mentioned the Koch Fractal crop formation in my article about the 911 events, because Flight 175 hit one Tower and Flight 11 hit the other. The combined 175 + 11 = 186, is associated with an alchemical triangle, as is the mirror number 681:

6 squared + 8 squared = 10 squared
or
36 + 64 = 100
Sun + Mercury = Earth
or
0.6 squared + 0.8 squared = One

[Link: http://www.greatdreams.com/Events/9_11_01/Amertrag.htm ]

To a large degree, Dan Brown's book was based on another book that came out in 1982. It is "The Holy Blood and the Holy Grail," by Michael Baigent, Richard Leigh, and Henry Lincoln.

The books have caused great controversy. It seems that many of the claims have been successfully debunked. However, there are many who believe that there is some truth to the ideas, and that the "Pauline Christianity" that came down to us via Saint Paul, Emperor Constantine, and others, may not be the "right" version.

Perhaps more than ever, people are questioning the source of the religions of the world. Many think there is a manipulation of some kind, possibly from extraterrestrial or extra-dimensional sources.

The great researcher, Jacques Vallee, has written about an unknown control system of some kind. Throughout history, people have been confronted by strange phenomena, which causes them to reevaluate their beliefs about the nature of reality. Such events are at the core of many if not all religions. Various prophets and religious leaders interpret the meanings, and they do not agree on all points.

Jacques and his associates have an article about "Incommensurability." I have linked it below in the Data Reference section.

Debunkers of crop circles and other strange phenomena seem to feel that all is explainable, and that there is no proof in terms of scientific evidence. My impression is that the debunkers want to halt investigations into crop circles, UFOs, and such. There techniques often leave an impression akin to a political "spin." The debunkers, of course, also cannot scientifically prove their own explanations. For the most part, we only have theories.

The primary question should not be, "Is it proven," but rather, "Is it worthy of further study."

One should keep in mind that the beliefs of people are important, even when they are not scientifically proven to be "true."  The beliefs effect the reality created, true or not.

Most debunkers of crop circles, for the most part, feel they are all man made, or created by some natural source, such as a plasma vortex. They seem to feel that the phenomena is basically meaningless, and therefore a waste of time to study. There is, however, an alternative argument. This is an excerpt from the article, "Arguments Against the Hoax Theory of Crop Circles":

"Presuming that all the crop circle formations are hoaxes created by humans, leads to a final few questions. Some estimated ten thousand crop circle formations have appeared all over the world in recent years. They are often considered to be "religious" symbols, such as the 1993 Bythorn Mandala, the 1997 Tree of Life, and two 1999 formations - the Winged Disk God and the Biblical Menorah.

"The religious beliefs of many people are being changed in the process. If the phenomenon is a hoax, it is on a very grand scale, and must involve a great number of people and resources. Why is it, then, that the Discovery Channel and other media or government organizations are not calling for a full investigation of this very serious matter?  Why do they heap ridicule on researchers who are trying to gather evidence and find the answers?  Is it not a serious matter that religious beliefs are being manipulated by unknown sources?  Should we not be concerned with their motives?"

[Link: http://www.greatdreams.com/crop/hoax/hoax.htm ]