Sure, 3-D printing has produced a five-story Chinese apartment building and is creating a bridge in Amsterdam. But one juggernaut of a machine was using similar tech to crank out entire houses seven decades ago, to believe a quirky item in Mechanix Illustrated.
A short story in the magazine’s June 1946 issue, dug up by weird-history collector Modern Mechanix, shows a huge contraption being conveyed by what looks like half a monster truck. Its operator would move it to the building site, then lower its mold over a pre-constructed house frame and start dumping in concrete. According to the article: