This seems like a modern reinterpretation of the Lo Shu Square using symbols from western alchemy. The Lo Shu Square is a magic 3x3 square of numbers which according to a Chinese legend appeared on the back of a turtle. See this picture for comparison with the one you posted:
![enter image description here](
According to the "Earlier Heaven" Taoist Bagua, one can associate the numbers 1,3,7 and 9 appearing on the turtle's back to the elements Earth, Fire, Water and Sky. In the flag you posted the triangles are Alchemical Symbols for the same elements (with the correspondence Sky=Air), although not in the same order. I have no clue regarding the middle symbol, though. One guess, but this is just speculation, is that it could be a stylized Yellow Dragon, associated with the center of the cosmos, and quintessence (the fifth element).