# Yin and Yang: Basics – Part 3/5: What is a fractal?

Yin and Yang are fractal concepts. Fractal theory was developed by the mathematician Benoît Mandelbrot who published his work in 1975. The main idea is that all self-growing structures, organic and inorganic alike, grow new structures similar to themselves. Organic examples are all life forms, inorganic include crystals and stars. Mandelbrot named one such structure a “fractal”, or several “fractals”.

Fractals can be defined with the following example:

A tree has roots. Then it grows a trunk which grows branches which again produce smaller branches. The structure the roots form looks similar to the structure of branches, and how the branches grow away from the trunk looks similar to how the smaller branches grow away from the bigger branches, etc. Therefore, the roots are a fractal of the branches, and the branches are fractal to the smaller branches. The sequence is however not important, only the similarity: The roots are also fractal to the branches, although there is the trunk inbetween, etc. The correct wording is either “is a fractal of something” or “is fractal to something”, with the same meaning.

The equations of fractal theory are increasingly used in computer games which require realistic graphics, to animate lifelike behaviour by putting such similarities on top of each other, just as self-growing structures would. But not only physical, but also psychological structures such as ideas and concepts can have “a life of their own” and grow structures in the same way as life forms do. Therefore, they are fractals which can produce new fractals. These two forms even affect one another which is the reason why concepts like Yin and Yang have been occurring multiple times in the course of evolution – in a new physical or a new psychological form.

Their sequence is still irrelevant for the classification of fractals. However, to know the oldest form of a fractal can be helpful since one can identify younger fractals more easily by following its history forwards. Concerning Yin and Yang, one of the oldest fractals is the division of responsibilities for sexual reproduction. In order to find related fractals, and thus the occurrence of Yin and Yang in other contexts, one can take a closer look at the evolution of sexuality in general.