sixty four permutations of eight

sixty four hexagrams represent the permutations of eight trigrams, each of which has specific associations: heaven, earth, fire, water, thunder, mountain, lake, wind;

held to represent fundamental elements of life through which human development can be fostered in which the refinement of consciousness is carried out; Taoist alchemy called it “cauldron of the eight trigrams”

The four timeless hexagrams are heaven, earth, mastering pitfalls, and fire. These are held to obtain in some way at all stages of practice.

the four quarters

linked mentions for "sixty four permutations of eight":

1. the four quarters
   combining the four signs Unification of mind; joining feeling and essence, real knowledge and conscious knowledge. Also sometimes defined as