A cold snap in early January caught plenty of humidity inside the house and, in fact, the attic temperature dropped so abruptly that the nails protruding through the roof iced over:
You’d think they were coated with plastic:
The incandescent bulb lighting the attic highlights the crystal planes:
As nearly as I can tell, the ice sublimes or melts-and-evaporates, because the plywood floor under the nails doesn’t have the drip marks you’d expect.
The Smell of Molten Projects in the Morning 
So many neat little discoveries all around us to find, if only everyone could be so observant and curious.
Winter is the only time of the year that I’m reminded of sublimation and re-describe the process to my wife. But come to think of it, the findings in the ice maker indicate we don’t use much ice year round.
Perhaps I’m easily amused, but I’ve always liked “small science” things like crystals and patterns. Even better: now I have a place to save them and show them off!
Stalactites in your attic!