Also known as yi jing. The Book of Changes. This 5000-year-old book is considered to be the classic Taoist text about the nature of change and how change occurs. The I Ching encompasses eight trigrams that embody the eight primal chi energies of which the universe is composed, according to Taoist thought. The eight expand to sixty-four by detailing how each of the individual trigrams impacts, mitigates, and expands the others when they are mixed. Ba gua chang is a mind/body/spirit practice that seeks to have an individual experience within his or her own being what the I Ching communicates intellectually.