The article discusses things that are illegal to build in most American cities, but the text is not available. Commenters discuss zoning laws, deed restrictions, and land-use ordinances, with some arguing that Houston is not an example of a city without zoning. The conversation also touches on the history of zoning and its effects on urban development. The lack of affordable housing options, such as rooming houses and micro-units, is also mentioned as a contributing factor to homelessness.