There are several pages of technical description to go along with this simple illustration. It's a work of genius, a new way of encoding information, a giant leap called FM radio. Which will be used to sell us stuff, but in stereo! keep on the sunny side, here .
No, totally straight, this was an incredible insight- or maybe application of known science in a new way. I understand just enough of the principles involved to appreciate it. Of course it's old technology now. Still works.