Tetractys

The tetractys (Greek: τετρακτύς), or tetrad,[1] or the tetractys of the decad[2] is a triangular figure consisting of ten points arranged in four rows: one, two, three, and four points in each row, which is the geometrical representation of the fourth triangular number.

[9][10] The Tetractys [also known as the decad] is an equilateral triangle formed from the sequence of the first ten numbers aligned in four rows.

So revered was this ancient symbol that it inspired ancient philosophers to swear by the name of the one who brought this gift to humanity.In the work by anthropologist Raphael Patai entitled The Hebrew Goddess, the author argues that the tetractys and its mysteries influenced the early Kabbalah.

It has been argued that the Kabbalistic Tree of Life, with its ten spheres of emanation, is in some way connected to the tetractys, but its form is not that of a triangle.

The occultist Dion Fortune writes: The relationship between geometrical shapes and the first four Sephirot is analogous to the geometrical correlations in Tetraktys, shown above under #Pythagorean symbol, and unveils the relevance of the Tree of Life with the Tetraktys.

The tetractys
Symbol by early 17th-century Christian mystic Jakob Böhme , including a tetractys of flaming Hebrew letters of the Tetragrammaton.
A tetractys of the letters of the Tetragrammaton adds up to 72 by gematria .
Ten-pin bowling pins in a tetractys
Coat of arms of an archbishop of the Catholic Church