The 'Sprinter': Your Friendly Neighborhood Printer
As a piece of worldbuilding for the CDRMX Project, this speculative architectural printer was in part born out of a joke while looking at pictures of abandoned castle homes in Burj Al Babas, Turkey, thinking this was the work of drone printers gone rogue.
Beyond its debatable esthetics — the designers allegedly attempted to create something that would "blend" with the local environment – lies an attempt at imagining what form rapid construction could take in the near future, and specifically the future of Mexico City. In this context, the task was to relocate entire neighborhoods and their people in a record time, all while adopting an approach to durable architecture that could withstand the seismic activity in the Valley of Mexico.
To achieve this, the Sprinter would not only produce houses, but also sidewalks, and drainage systems, and would do so with a mix of polymer and geopolymer concrete, carefully coordinated to create "soft" foundations that can absorb tremors caused by potential earthquakes.
2022 edit regarding 3D printable concrete
In this fiction we imagined our construction material to make use of rubble, sediment, and whatever would be left after demolishing old neighborhoods to re-make some lake space. While there is substantially less of a spotlight on 3D printing, fantastic materials are being imagined today to achieve such architectural forms minus the "nasty" concrete. If you want to geek out on that, here's an example from a small dutch company called Omlab presenting their approach with circularity in mind.