I have a deep love for all snowflakes. I often open a book, "Kenneth Libbrecht - The Art of the Snowflake, A Photographic Album" to see how complex they are. So when I found a paper on how to model snowflake growth, I had to implement it.
Modeling snow-crystal growth: A three-dimensional mesoscopic approach, by Janko Gravner and David Griffeath.
They are drawn using POV-Ray.