Three (3)

Pythagoreans regard Three as the first complete number: it consists of an initial part, a middle part, and a final part. The introduction of the middle part breaks up the black-and-white duality.

Two points define a line, a linear scale of choices. Three points define a plane, with an infinity of possible linear scales.

Humans tend to reduce everything into a one-dimensional duality, which may cause unwanted cognitive lockups - a need to choose between two options and an unability to see alternative aspects. The Rule of Three requires at least two dimensions, which results in much more cognitive freedom.

The Setun series of Soviet computers used a balanced trinary base (-1, 0 and +1) instead of binary (0 and 1).

Tai Xuan Jing is a trinary alternative to Yi Jing, presenting a system of 81 trinary tetragrams instead of 64 binary hexagrams.

Three binary splits produce eight choices, symbolized by the eight trigrams.