Koch snowflake – Wikipedia

The Koch snowflake (also known as the Koch curve, Koch star, or Koch island) is a fractal curve and one of the earliest fractals to have been described. It is based on the Koch curve, which appeared in a 1904 paper titled “On a Continuous Curve Without Tangents, Constructible from Elementary Geometry” by the Swedish mathematician Helge von Koch. The Koch snowflake can be built up iteratively …

https://en.wikipedia.org/wiki/Koch_snowflake