this is the behavior of a HEAVILY OVERWORKED tower!
remember that if your tower is exceptionally tall and narrow (like these) and/or carrying an extraordinarily heavy load (like a vault room full of gold, or a storeroom of priceless artifacts), you should be setting aside a day every lunar cycle to put it in rest mode (wards down, magically-animated servants asleep, etc;) to prevent catastrophic collapses such as these!






