Another thing in the category of abusing font capabilities is Harfbuzz (OpenType engine) WASM, which if compiled into an application allows fonts to basically run any code. A few examples are an LLM or a Tetris font. Apparently this WASM support is in the font rendering for Chrome and Firefox supposedly.
I was really tempted to try to use it to make a Harfbuzz OS.
I can't tell if the results are just very bad or my browser is just not rendering properly. I feel like its probably the later but it would be cool to have a reference picture to be sure.
Images of what it's supposed to look like would really help, as I'm pretty sure none of my browsers are rendering it as you hoped. For me in Chrome the first image looks vaguely like a landscape, with no identifiable features, and in Firefox it looks like grass (both on Android). The dog and tree shapes look distorted and glitchy, but recognisable if you know what they're supposed to be.
I was really tempted to try to use it to make a Harfbuzz OS.
https://fuglede.github.io/llama.ttf/
FWIW, didn't have any luck with the generator at the bottom, could be user error.
I spotted a typo: "font's like".
I'm primarily testing on Vivaldi on MacOS but also confirmed working on Chrome on MacOS.
Tۜۜۜۜۜeۢۢۢۢۢsۛۛۛۛۛtۙۙۙۙۙiۚۚۚۚۚnۨۨۨۨۨg۫۫۫۫۫
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|ۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗۗ|ۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘۘ|ۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙۙ|ۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚۚ|ۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛۛ|ۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜۜ|۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟۟|۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠۠|ۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡۡ|ۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢۢ|ۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧۧ|ۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨۨ|۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫۫|۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬۬|ۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤۤ.
Tۜۜۜۜۜeۢۢۢۢۢsۛۛۛۛۛtۙۙۙۙۙiۚۚۚۚۚnۨۨۨۨۨg۫۫۫۫۫
Author's specific examples: Aۜۢۛۜۢۛۜۢۛۜۢۛۜۢۛ Bۙۚۨ۫ۙۚۨ۫ۙۚۨ۫ۙۚۨ۫ Cۣۣۣۣۣۣۣۭۭۭۭۭۭۭ Dۣۭۣۭۣۭۣۭۣۭۜۢۜۢۜۢۜۢۜۢ
Edit: Apparently, you cannot write direct html entities.
Edit: And you cannot directly write the characters either. Rendering seems rather finicky on Firefox, while Chrome seems somewhat consistent.