How Mother Nature creates art on frosty windows

SEATTLE — When nature imitates art or is it the other way around?

Cold mornings in Puget Sound can lead to spectacular patterns of frost resembling ferns and flowers.

As water from the air lands on a really cold surface, like a car windshield, the water molecules freeze instantly to form patterns of ice crystals.

Sometimes the water molecules align into one uniform sheet of frost. But tiny imperfections in the glass or a speck of dust get in the way, forcing the molecules to branch out into different directions and shapes that, to us, look like feathers or ferns.

Mathematicians call this fractal design, which is observable in all of nature. But the fern frost and ice flowers are by far my favorite!