Patterns

When it rains and then freezes - or rains on top of ice as it did last night - then we get a whole range of wonderful shapes on the roof of the conservatory, like this one from last December.

It is unusual to get ice on the windows as well, yet this morning every pane was covered and the view obscured. Within the frost, though, there were lots of delicate patterns like this one , which must form according to some rule of physics but seem infinitely variable too.