A Spectre Is Haunting Unicode (2018)
I love this.  There are lots of characters in Unicode I'd love to know the history of, but searching for such things is hard, at best.<p>The one I've stumbled across recently are the "Negative Squared Latin Capital Letter" (1F170 - 1F189 [1]).  The 26 letters are there, but "A", "B", "O", and "P" are special.  Blood types and a parking symbol.  Sure, but why?  Why was it decided we needed all of the Latin letters in inverted squares, except those?  Why aren't they their own symbol?  I'm not complaining here, I just want to know the history.<p>I'd also love to know the history of the other Latin letter ranges.  It feels super odd to me to have, say the "Mathematical Bold Fraktur" range of characters (1D56C - 1D59F [2]).  What's the history of including a font in Unicode?  Why did we stop with the few that are in there?<p>This is probably somewhere online, but I can't find it.<p>[1] <a href="https://unicode-search.net/unicode-namesearch.pl?term=negative+squared" rel="nofollow">https://unicode-search.net/unicode-namesearch.pl?term=negati...</a><p>[2] <a href="https://unicode-search.net/unicode-namesearch.pl?term=mathematical+bold+fraktur" rel="nofollow">https://unicode-search.net/unicode-namesearch.pl?term=mathem...</a>