I would love to see this feature in game - a signal fire which could be built in a town and when actually put on fire then the smoke should be visible in some distance - say everyone who’s away by two or three tiles gets a notification that they can see smoke coming from say northwest, or from some exact location even.
As it is now there is really hard to create a common defense system for towns. Even towns which are away for like two tiles are pretty much on their own - sending a pet with message takes too long as for an urgent situation. Imagine trying to alarm cities which are away by as much as 8 tiles. And with the use of Signal Fire the message would be pretty much instant.