Take the tetra out of a historical context......
The "four" (tetra) are found in all religions and cultures worldwide.
The four stags of the yggdrasill tree in Scandinavia for instance.
https://en.wikipedia.org/wiki/D%C3%A1inn,_Dvalinn,_Duneyrr_and_Dura%C3%BEr%C3%B3r
Or what about the four "heavenly Kings" in Buddhism.
https://en.wikipedia.org/wiki/Four_Heavenly_Kings
The tetramorphs of various cultures.
https://en.wikipedia.org/wiki/Tetramorph
The lamassu of the Assyrians.
https://en.wikipedia.org/wiki/Lamassu
The Bacab of the Mayans.
https://en.wikipedia.org/wiki/Bacab
And loads more.....go google for yourself......all over the world.
If you notice....they all represent the four cardinal directions/four seasons/elements.
As does the cross and swastika....yin/yang and lotus flower.
The Jews take on the "four".....are the four letters.....tetragrammaton........but they all represent the same thing....the four directions/seasons/elements.......Jehovah the god of matter and nature.