The most beautiful snowflake photos you’ll ever see, captured with a cheap DIY camera
The shape of a snowflake is dictated by the micro-environment of the snowflake as it forms (while falling through a cloud). The reason almost every snowflake is symmetric is because the structure of an ice crystal is a six-sided hexagon — and so each “arm” of a snowflake grows from one of those points. Depending on the temperature and humidity, water molecules attach themselves differently, creating different shapes.
Because snowflakes are so small (on the order of a few millimeters), the micro-environment is very similar for the entire snowflake — but even still, there can be small changes across the diameter of the snowflake, resulting in nonsymmetrical growth.