Was trying to get to my plane at Dulles International airport in Washington, DC. There are a number of terminals, and a train connecting them. So we got on the train, expecting it to do the usual thing – run in a (topological) circle, or maybe back and forth along a line, between the terminals and perhaps a rental car lot. And there was a map on the carriage wall…

Pretty soon it became clear that the train follows its own logic, and worse – the map shed absolutely no light on what was going on. We men are supposed to be good at spatial orientation, and I’ve done my share of map navigation, but I still can’t figure out what the hell this map is trying to convey. The fat white lines aren’t even on the “Map key”!
In the end we got off at the next stop, and a kind airport employee told us how to trek on foot to our target terminal… so all ended well. But the cartographers of Dulles should really get their act together!
This is hilarious, as the “formal” map on their web site is totally different, 90 degrees rotated: https://www.flydulles.com/travel-information/airport-and-terminal-maps
The fat white lines seem to represent the actual walkways between the gates (within the buildings), from A to B and from C to D. The carriage map must be an old version…