We've not seen much frost this winter so far, but this morning produced crunchy grass and this marvellous pattern on the bonnet of the car. (The car is black; I can only assume the blue sky reflecting off it produced this deep blue shade.) It's quite the most complicated fern shape I've seen in frost.
But do you remember frosty ferns on the insides of your windows in the past? (I'm wondering as I write that if anyone still does ... make no assumptions about double glazing and central heating!) My bedroom was always pretty chilly when I was young; I clearly remember putting my clothes on under the blankets to avoid the shock of the cold air. And yes, there were these wonderful fern patterns to compensate for it, or so my father would point out with some glee. The warm place was always the kitchen; till I was ten I lived in a flat with a kitchen range that was always on, and when we then moved house there was a neat little solid fuel boiler that my parents installed and which was still functioning when we sold the house not all that many years ago.
It wasn't just in childhood that we had frosty windows: when we moved to Dunoon and bought the house we still live in we had single glazing in the original sash windows; once when there was a bit of a blizzard going outside I remember going into the bedroom and seeing flakes of snow puffing upwards at the sash cord in mid-window. And we didn't have central heating until I retired.
Come to that, I don't have any in the bedroom to this day ...