HTML Radio Buttons: A blast from the past!

So there I was sitting in my C/Unix class at Harvard barely paying attention to the professor as he talked about HTML forms (!) when I heard him start talking about the history of the HTML radio button. I often wondered why they were called "radio" buttons so I shifted my attention and listened.

He started by trying to explain to a room full of people a third his age how car radios did not always have tiny touch-sensitive buttons and that they used to be single mechanical buttons that when one was pressed, the other would come out (much like the old cassette-based walkman's).

This little fact fascinated me because I have been using HTML radio buttons for so long and until now, I have been so oblivious to the history behind their name. A quick search on Wikipedia confirmed my professor's story:

A radio button or option button is a type of graphical user interface widget that allows the user to choose one of a predefined set of options. They were named after the physical buttons used on car radios to select preset stations - when one of the buttons was pressed, other buttons would pop out, leaving the pressed button the only button in the "pushed in" position.