So, I was prepping for Hardmode, getting tired of my NPCs wandering in front of my chests, so I figured I'd sink some of my plentiful resources into rebuilding my base into something beyond a floating box. If I do say so myself, I think it came out rather nice....
A couple of notes: The Daytime image is slightly newer, I tweaked a bit more. I still need to do a little more rearranging of chests and such, and I'll be sticking a couple of armor-clad mannequins in the upper corners. The walls in the central area are iridescent brick, painted green. Below the base (underground) are a couple of pits, liquid generators, a statue-farm setup (I swap in statues at need), and my new arena. Those rails lead to my skybridge.
The side exits look a little weird, but they do work OK, with the doors open I can run smoothly from the rails on either side to the rails on the other. I'm thinking about some actuated caps to seal off the bottom if I need to for an event.
Note that some of the NPCs are currently housed elsewhere, but their rooms (along with the "blank" rooms) will be spares for incoming Hardmode NPCs. I think I provided sufficient spare space for Hardmode equipment and more chests, too -- if I need more space I will continue the top to a pyramid or suchlike.
By Day:
By Night:
Hmm. Tried a Blood moon image, but it didn't look much different than the night.