In astrology, the dot in the circle is a symbol of the sun, and so it's sometimes called the "sun sign". In the Kabbalistic numerology, according to Godwin's Cabbalistic Encyclopedia, the Sun is associated with the number 666. But the dot in the circle is also said to be an androgynous symbol in that the point at the center represents the phallus, and the circle represent the vagina, or female principle, thus making this symbol yet another symbolical synonym of Solomon's Seal in the occult world.

Albert Mackey, Masonic scholar and author, wrote that "among the ancients, the Supreme Deity was bisexual, or hermaphrodite, including in the essence of his being the male and female principles, the generative and prolific powers of nature. This was the universal doctrine in all the ancient religions, and was very naturally developed in the symbol of the phallus and cteis among the Greeks, and in the corresponding one of the lingam and yoni among the Orientalists; from which symbols the masonic point within the circle is a legitimate derivation. They all taught that God, the Creator, was both male and female." (Albert Macke, The Symbolism of Freemasonry, XXIV.

Churchward, a Freemason, informs us in his book "The Acrcana of Freemasonry", that the point in the center of circle, which is a "symbol of great importance in Freemasonry", according to Mackey, also is a symbol of the All-Seeing eye: "It was previously stated that the Pole Star North was symbolized by the one All-Seeing Eye, also called the Great Judge of All; also that the dot or Star at the summit of a Cone, or Triangle, was the Ideograph for Horus, god of the Pole Star North. The point in the centre of a Circle is equal to the point at the top of the Triangle, and this Glyph is equivalent to the Eye; the two are synonymous." (Churchward, The Arcana of Freemasonry, page 188)

Thus, if the dot in the circle is a emblematically analogous or synonymous with the All-Seeing Eye, and if, further, the Blazing Star, Eastern Star, or inverted pentagram signifies the All-Seeing Eye, it follows that if the Eastern Star is synonymous with the Hexagram, then, likewise, the circled dot is synonymous with the hexagram, or Solomon's Seal. Also, since the hexagram's numerological signature is 6,6,6, perhaps it's true to say that in making the Obelisk of the Washington Monument 666 feet, the hexagram was thereby numerologically suggested also. The obelisk itself is 555 feet, or 6660 inches, but with with the height of the base included, which comprises 20 percent of the total length of the edifice, the entire monument is said to be 666 feet high.

Interestingly, then, the famed crop circle of July 11, 2001, at the Gog Magog hills area in the U.K., which was laid down just two months to the day prior to the 9-11 terror attack, exhibited the exact same numerological signature as the Washington monument. The crop circle, consisting at first of simply a dot in a circle, had a diameter of 666 feet. The width of the circle surrounding the dot was 18 feet (6 + 6 + 6):

Mackey, Freemason and author of The Symbolism of Freemasonry and other Masonic tomes, wrote in writing on this symbol: "But the Phallus or Lingham was a representaiton of the male principle only. To perfect the circle of generation it is necessary to advance one step farther. Accordingly we find in the Cteis of the Greeks, and the Yoni of the Indians, a symbol of the female generative principle, of co-extensive prevalence with the Phallus. The Cteis was a circular and concave pedestal, or receptacle, on which the Phallus or column rested, and from the centre of which it sprang." (Makey, The Symbolism of Freemasonry as presented in the religious texts internet archive.)