Ken Jennings in Parade Magazine:

While the child in question may well be unique, the crystalline lattices that fall from the sky sure aren’t. This adage dates back to Wilson Bentley, a turn-of-the-century Vermont man who was so fascinated by snowflakes that he spent his life perfecting a process to photograph them. In a series of journal articles, Bentley argued that no two flakes were alike.

At a molecular level, of course, he was right. There are something like a sextillion molecules of water in one snowflake, and the arrangement of hydrogen and oxygen isotopes within them will never be duplicated. But at a more meaningful level—that of microscopic inspection—Bentley was wrong. The simplest snowflake shapes are likely repeated all the time.

Read as Jennings busts 14 more myths at here.