Let's imagine for a moment that some entity exist, immortal, invincible, and with extremely advanced technology at its disposal.
Such a life sooner or later become boring, and so that entity decide to travel the galaxy insulting people the multiverse, looking for the remains of our lovely bearded forts and comparing the layouts, trying to pin diverse forts to the same architect, analyzing the many style currents, pretty much what our archaeologists do(or I think they do) when they uncover a ruin.
So, what would your fortresses main defining feature be, if any? Are there anything that sooner or later, consciously or unconsciously, emerge in nearly every fort? Would the Eternally Prolonged, Multiverse-hopping Archaeologist find an easy to recognize mark of your hand in the ruins? And would it be delighted or disgusted by it? Or maybe it will be baffled by a completely chaotic style?
Share your findings, I'll start:
I recently noticed that every fortress of mine is built in a mountain side, with the entrance conveniently guarded by stone spurs, and there is some sort of Endless Staircase, a 3x3 up/down staircase that goes from the hot stone depths up to the mountain pinnacle(with all the bother of going through caverns).
The general layout varies a lot, but the staircase remains constant through the forts, and many of those forts appears to have been abandoned after such staircase pierced a cavern layer full of hostile monsters which overwhelmed the still immature military...