Snowflakes are interlocked bunches or aggregates of ice crystals that fall through the Earth’s atmosphere as snow. Snowflakes usually appear white in color due to the diffuse reflection of the whole spectrum of the visible light by their crystal facets. Snowflakes have a wide variety of intricate shapes primarily determined by the temperature and humidity of the environment at which they are formed.
Snowflakes have their own history of discovery and study. In this regard, one can note Wilson Bentley as one of the first known photographers of snowflakes (early 1900s) who perfected a process of capturing images of snowflakes on black velvet before their melt or sublimation. Ukichiro Nakaya should undoubtedly be noted in the history of snowflakes since he established a general classification of natural snow crystals based on over 3000 photomicrographs (1930s) and related the crystal shapes to their forming conditions. Nakaya’s classification of natural snow crystals and related temperature-humidity diagrams were modified and supplemented by Magono and Lee (1960s) who considered eight broad classifications and 80 individual variants for shapes of snowflakes. For modern classifications, one may refer to documents like “The International Classification for Seasonal Snow on the Ground” by Fierz, C., Armstrong, R.L., et al. (2009).
In this regard, it may also be interesting to read about the Koch snowflake. The Koch snowflake, also called Koch curve, Koch star and Koch island, is a fractal whose shape resembles a snowflake. It is based on the Koch curve, described in a 1904 paper titled "On a continuous curve without tangents, constructible from elementary geometry" by Niels Fabian Helge von Koch, a Swedish mathematician.
One can construct Koch snowflake by starting with an equilateral triangle and recursively changing each line segment by division of it into three equal-length segments and substitution of the middle segment of the new three segments by two equal segments where substituted and added segments together make an equilateral triangle pointing outwards.