"There must be some definite cause why, whenever snow begins to fall, its initial formation invariably displays the shape of a six-cornered starlet. For if it happens by chance, why do they not fall just as well with five corners or with seven? . . . Who carved the nucleus, before it fell, into six horns of ice? --From "On the Six-Cornered Snowflake," by Johannes Kepler, 1610"