You have not filled it.I got lucky and stumbled upon one of those towers a few thousand blocks out while searching for the cliffs biome in my current game and spawned in the same chunk as one in a previous game. Sometimes luck is a harsh mistress.
I still haven't figured out the use of the crystal right-click UI yet. It just makes a "wrong sound". Has the function been implemented yet?
Here.Also what place is better to post feature ideas? Here or github?