Trigrams. Fire, Wind, Water, Earth iirc.

There’s four more. Mountain, Lake, Thunder, Heaven, again iirc

Stacking these in pairs gives the 64 hexagrams.

For instance, Wind over Lake, equals unseen force (wind) manifesting visually (rippling the surface). It’s pretty high concept. Just the thing for a priestly (weak) class to control or manipulate a royal (strong) class. Nothing new about that. Ancient kings everywhere consulted oracles before waging war. Who’s really in control?

Ancient Taoists invented gunpowder. They were looking for an elixir for indeterminate lifespan, for the Emperor. It’s certainly been used to protect those in power, and keep those seeking power busily killing each other.