Grace, Set Upside Down

In 1845, a St. Louis compositor setting Der Lutheraner seated one letter upside down, and the word Gnade — grace — went out to the subscribers as Guade. Nobody caught it for 180 years. How hand-set type worked, how a turned letter happens, and how an AI correction pass that was taught to fix its own mistakes and respect everyone else's found it. From the essay at news.collver.biz.