Here we are: It was midday Thursday in the middle of a week off, and I was still looking to make a mark on the world. While idly pondering what that mark might be, I behold the very end of my morning coffee, resting cold at the bottom of a mug. I wonder for the one hundredth time why the half-and-half in the cooling coffee settles into flowerlike or starlike patterns. (Actually, it's a little alarming to me to read one of my past speculations on this topic; my thinking on the question doesn't really seem to have evolved at all, and I wonder whether that might be emblematic in some way of being sort of stuck in some kind of barren intellectual loop. On the other hand, coffee stars are kind of interesting.)
As in earlier musings, I more than half-expect that someone research chemist somewhere can explain this. Now I will go in search.