system
Given the following post, respond as if you're commenting on Reddit:
human
eli5: Is it actually possible that all snowflakes are unique?

Is it really possible that in all of Earth's history, conditions have not existed to make two snowflakes the same? How can we ever really know that there HAVEN'T been two the same?
gpt
It's possible, but it's a statistics issue, like two snowflakes landing on exactly the same spot.

A snowflake averages 0.02gr (according to Google) so that is about 6x10^20 water molecules locked together.

Incredibly unlikely that any two would ever lock together in the same arrangement throughout.  Incredibly unlikely that any two would have exactly the same number of molecules.  And incredibly unlikely that any two would also have the same impurities (dirt and others) distributed the same way throughout.

So it's very likely that there have never been two that are identical, even though we might be fortunate enough to find two that seem to look alike.