system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does one ‘arm’ of a snowflake know what to look like to match the others?
gpt
It doesn’t, but the way the crystals grow is affected by a bunch of little factors that are shared more or less across the flake so they grow the same way. This isn’t always the case, so many flakes grow asymmetrically or are deformed before they get to us.