Addition Font
litherum.blogspot.com
litherum.blogspot.com
This ended up being far too labor intensive to get right, but it still seems like a cool idea for someone else to tackle eventually.
(The ligatures are subtle -- try typing "OOOO" to see an example.)
For reference IBM Plex (Mono) fonts that I’ve been using since release do not have warnings and work perfectly, however when I re-encoded them to add ligatures it turned out there were errors with the fonts, macOS warned me and I ignored the warnings, then I noticed higher than expected CPU usage from apps where I had enabled the modified fonts incorrectly.
It is a pity. I could name dozens of its great ideas that are still waiting to be re-invented by the mainstream languages of today.