IBM'S INGENIOUS SOLUTION FOR A TYPEWRITER WITH SWAPPABLE FONTS

Summary from the TLDR Design newsletter

The typewriter was a dominant communication device of the 20th century. It came with default fonts — keys connected to typebars. Replacing dozens of typebars was not trivial, so the font you used was the font your typewriter came with (typically Courier), until 1961 when IBM released an electric typewriter that would allow you to change the font in just seconds.