I'm thankful for my family and the great support I've gotten from them.
I'm thankful for the healthcare system which has provided a great deal for my brother, even though progress is slow.
I'm thankful for my friends, their interest and enthusiasm.
I'm also thankful for HN and the greater tech community. My parents do not have a higher education and without HN and the surrounding internet I'm not sure I'd have pursued one.
Not really an answer but if you check out provability section of https://en.wikipedia.org/wiki/Löb's_theorem you'll find a formula very similiar to the haskell type, together with a proof in modal logic.
There's a gradual color change in the header of
https://tryenlight.github.io/guide, which is fine and all except the text isn't legible when the color is red.