The Super-R run-command dialog on Windows, and Notepad make it look crazy

That iMessage rendering looks correct, just typeset differently.

Yup. I practice western calligraphy but haven't been able to make much inroads into Arabic. Partly because of the lack of high quality instruction material (which is available as books for Western calligraphy) and partly because of the complexity. The fact that it's right to left and I'm right handed presents some challenges too (my hand will come over letters I've just written and there's a risk of smudging them). The nibs are usually cut the other way and I'm still struggling drawing basic letters.

Islam prohibits representational art and so, except for a few pockets, all the skills of Muslim artists went into two things - Calligraphy and geometric tessellations (what's called "arabesque" and which you see on mosques, rugs etc.). The calligraphy itself has several hands (which is what we call "fonts"). The most popular one is called https://en.wikipedia.org/wiki/Naskh_(script) which is the one used for the copies of the Koran from Saudi Arabia. It's very legible and doesn't lend itself to too much flourishing. The Basmala glyph mentioned in the article looks like Naskh with the S of Basmala (س) elongated. There are others too. Thuluth (which is used in the copies of the Koran for ornamental work like the titles of the chapters), Nastaliq (which people often call Urdu or Persian because of how those languages are usually written in this hand), Kufic (which is an angular hand that overlaps with tessellations in ornamental work), Mughlai (which is a denser hand that's common in the Indian Subcontinent) and several others. There are even local variants with which you can identify geography. This style is specific to the Malabar coast in Kerala and, as far as I know, it's seen only there. https://en.wikipedia.org/wiki/Arabi_Malayalam_script#/media/...

> And “kashida” is a persian word not Arabic, the Arabic one is probably “maddah”.

I thought it was "tatwil". I could be wrong, though. An interesting article on Arabic typography, whose correctness I can't judge:

https://www.khtt.net/en/page/1821/the-big-kashida-secret