Most people think no two snowflakes can look alike. However:
Although there is indeed a certain level of unknowability to the question of snowflake alikeness, as a physicist I find that I can address this issue with some confidence. …. The short answer to the question is yes — it is indeed extremely unlikely that two complex snowflakes will look exactly alike. It’s so extremely unlikely, in fact, that even if you looked at every one ever made you would not find any exact duplicates. The long answer is a bit more involved — it depends on just what you mean by “alike,” and on just what you mean by “snowflake:”
• Nano-snowflakes can be exactly alike.
• Small snow crystals can look alike.
• Larger, complex snowflakes are all different.
I am quite taken with the possibility of making your own snowflakes, snowflake watching, and knowing the snowflake hot spots. Perhaps it’s because I remember organizing projects with my younger brother and sister to prove that two snowflakes could indeed look alike. Still looking.