It's called a unicursal hexagram. Here's a LITTLE background information about it.


 

The Unicursal Hexagram symbolizes the union of the man with the divine. As with the hexagram used in the Star of David, this six-pointed star represents "as above, so below," but because this symbol is formed of only one line, rather than 2, it further represents that above and below, human and divine are one.

It symbolizes the void we came from and the void we shall return too. It is Humility.

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