Jigsaw Block Fix (Tutorial)

This is just something I wish would have been made clearer to me earlier, as it would've saved me a lot of head scratching. If you're using jigsaw blocks, I can almost guarantee you've run into this problem: the names and pools are all set properly, the distance and steps are fine, but for some reason, blocks in certain positions just refuse to generate.

As it turns out, there's a bit of a hidden system to how jigsaw blocks generate that will cause them to fail even if they would otherwise behave normally. Jigsaw blocks are considered either INTERIOR or EXTERIOR, depending on whether they generate a new structure entirely outside the previous one, or entirely within the previous one. Therefore, if you want to randomize an interior room, the bounding box of the new structure must fit entirely within the previous one, or, conversely, cannot intersect with it. If the resulting structure would only be partly within the previous one, it will fail to generate. Similarly, an interior jigsaw block is not allowed to generate new structures outside its parent structure, though exterior jigsaw blocks can obviously generate their own interior structures.

This took a stupid amount of time to figure out, and I haven't really seen this issue brought up in other tutorials, or even the wiki, so I just wanted to get this out there on the off chance if helps someone. (Why the hell this is part of the game is another question entirely, but at least the issue seems mostly avoidable if you know how it works.)