Kowloon is certainly an example of what can happen in ultra-high-density environments, but I think most of the developing world is a good example of what would

Kowloon is certainly an example of what can happen in ultra-high-density environments, but I think most of the developing world is a good example of what would happen in most of the US without building regulations. A GIS of "housing <developing country>" provides a reasonably good example of such housing. Think somewhere between wooden shed, to modestly constructed masonry and no electricity.