“The second reason for its having been chosen as the symbolical representation of the Universe, and of our earth, was its form.
It was a Circle and a Sphere; and the ovi-form shape of our globe must have been known from the beginning of symbology, since it was so universally adopted.
The first manifestation of the Kosmos in the form of an egg was the most widely diffused belief of antiquity. It was a symbol adopted among the Greeks, the Syrians, Persians, and Egyptians.
With the Greeks the Orphic Egg was part of the Dionysiac and other mysteries, during which the Mundane Egg was consecrated and its significance explained, Porphyry showing it a representation of the world.
Both in Greece and India the first visible male being, who united in himself the nature of either sex, abode in the egg and issued from it.
This “first born of the world” was Dionysius, with some Greeks; the god who sprang from the mundane egg, and from whom the mortals and immortals were derived.
In view of this circular form, the “|” issuing from the “0” or the egg, or the male from the female in the androgyne, the 10, being the sacred number of the universe, was secret and esoteric, both as the unit and cipher, or zero, the circle.”
H. P. Blavatsky