Baarle-Hertog and Baarle-Nassau, one Belgian and one Dutch, are braided together so tightly that the border runs through gardens, shops and a few front rooms. The rule for a house that straddles the line is that it belongs to whichever country its front door stands in, and so, now and then, someone has moved the front door. With a builder and a weekend, a house can move to another country while the kitchen stays exactly where it was. I like what the rule chose. Not where you sleep, not where most of the floor is, but the place where someone knocks.