Gua figures

Gua (kua) figures are an ancient form of binary combinatorics, most commonly present in Africa and Eastern Asia. We prefer Chinese terminology when discussing guas.

A gua consists of a fixed number of horizontal lines (yao), each of which can be in two alternate states - yin or yang. Yang is represented by one rock, stick or other elementary symbol, while yin is represented by two of them.

When converting guas into modern Western binary numerals, we consider yin to symbolize zero (0) and yang to symbolize one (1). The bottom yao corresponds to the most significant bit.

In Asian gua systems, the most common basic gua is the three-bit gua (trigram), while in African systems it is the four-bit gua (tetragram). On both continents, the actual gua used in divination practices usually consists of two basic guas (six or eight bits, respectively).

European names of gua figures of specific sizes:

Length	Name	Number of possibilities
0		1 (the cosmic egg)
1	monogram	2 (yin and yang)
2	bigram	4
3	trigram	8
4	tetragram	16
6	hexagram	64

Guas are used for divination in all cultures where they are known to exist. Individual guas have been attributed to various archetypal ideas such as gods, elements, directions and numbers.

Some gua-based systems include Yijing, Sikidy and Odu of Ifa.