I increasingly find the no two alike thing exasperating. Almost nothing in nature above the subatomic/atomic/molecule level is "alike" in crystals or anything else. Making BIPM spheres of counted atoms does not truly make them identical. Cubic crystals of salt will have differences.

At the level of detail most people can discern, I suspect many morphological forms of ice crystal are very alike, and we have to resort to the small imperfections to get to not alike.

Nothing is exactly the same. That's what discrete countable things are: distinct.

(Of course it's semantics. And poetic license. Most snowflakes are trivially unlike, and those which are nearly alike have discernible difference if you go looking for them. As do cells, flowers, grains of sand.. )