December 11. Again, the conversations with my son tumble over, from one dimension to another. What came first, the fruit orange or the color? What would it feel like to travel at the speed of light? Why does it seem so easy for celestial bodies to orbit each other, why don’t almost all encounters end up with the bodies colliding? Or do most of them? – Again, I’ve explained GPS and special relativity. It’s a great story, but shouldn’t I know a lot more stories like that? Not discover a new one every day? – But I’ve also made it my goal to discover how the logs burn here in the fireplace, and the toilet here on the first floor of the house we’ve rented, right next to the front door: sparkling clean and ice cold, like all such toilets.