What’s with the number buttons being available with no “OK” or “Enter” option?

That is a lot of Morse code happening in this day and age!

I can’t help but wonder what is being transmitted, the airwaves have held a constant sense of mystery and wonder ever since I was a boy, growing up in a town with no FM stations and nested between hills that blocked all FM signals from the big cities of Southern California.

But at night, when the entire region was covered in the low clouds of the marine layer, there were nooks and corners of the town where the radio signals came in loud and clear. Chasing those FM signals became a sort of hobby for some of us in town, we took along a portable radio/cassette player and recorded tapes of live late-night music from Los Angeles or San Diego.

Every once in a long while we picked up signals from stations too distant and weak (at the source) to normally make it as far as my town, but which somehow became amplified in foggy conditions, some far-out-there music from college or pirate radio stations.
The thrill of stumbling upon something like this while scanning the lower extreme of the dial, then suddenly getting a blast of Killing Joke (post-punk) or Koch (lo-fi reggae), was like finding myself in Herman Hesse’s “Steppenwolf” theater: “For Madmen Only - Price Of Admission - Your Mind”.

Through the following years and few decades, I explored AM and shortwave, and I can’t even begin to describe the sensation I felt while scanning the dial very late one night and being confronted by a Numbers Station, that nearly robotic female voice reciting: “eight, nine, five, seven, seven… nine, three, eight, one, seven… four, seven, six, one, seven…”

It was only after all this that the internet came into being, and the very first thing I did with it was search for live radio, the very first app I downloaded was Real Player (“buffering”… lol).
But the romance of electromagnetic waves persists in me, I only listen to stations that also transmit over the airwaves somewhere in the world, there’s a feel to them that online-only stations cannot seem to be able to replicate.

This mathematical visualization is beautiful, like a work of art.
But what is it exactly that we are looking at here?
The continuous vertical and horizontal violet lines, the bursts of light color like a seismograph needle, they look like a word cloud flipped 90° and seen from afar. What do they represent?