--- --- Here is a door that stays closed permanently. One cannot see / "Line of Sight" through the door, but it can be walked through (I didn't observe if walking through the door actually also deduct the "door-toll" in time-units). ((EDIT: Walking through the door(-way) uses the extra TUs.)) The door itself cannot be manually opened or closed (then again, it is permanently closed; I haven't tested if it can be destroyed). ((EDIT: Door can be interacted with, but the door itself sta