Wavefont and linefont: show waveforms, spectrums and charts without using graphics

Wavefont is a typeface of smooth vertical bars, to allow rendering of waveforms, spectrums, bar charts and the like using text. The playground demo is a thing of beauty. I was able to make it look like an old 8-bit computer with 2:1 aspect ratio pixels!

See also Linefont, the same thing but for line charts and graphs.

It's great, but I'm always wary of font cleverness like this. I could never get into Mastodon because the popular gateway site used a font for rendering icons, but it would never load, leaving the site a mess of default unicode boxes and me with that internal scream of "perseverance will result only in further suffering!"