>>cs702+(OP)
Author here if there is any questions.

Source code: https://github.com/Erk-/programmable-fonts

You can also see actual uses of this WebAssembly embedding to show that is not just for fun here: https://github.com/harfbuzz/harfbuzz-wasm-examples

>>HanCli+ym
Game of life is certainly possible someone saw my Bad Apple font and not only reproduced it, but also made a Maze [0]

So the biggest issue is that you need something that uses harfbuzz where you can recompile and add a flag. If you look in this repo there is something precompiled for Mac [1] which was the software I used as well. You can also build harfbuzz as described here [2] and load it into some program. I used to just install it globally on arch and then use Gimp for the Bad apple example.

And lastly the same person who made the maze also made a way to use LD_PRELOAD to load a custom harfbuzz into arbitary software so you can follow that guide as well: [3]

[0]: https://github.com/hsfzxjy/Harfbuzz-WASM-Fantasy

[1]: https://github.com/harfbuzz/harfbuzz-wasm-examples

[2]: https://github.com/harfbuzz/harfbuzz/blob/main/docs/wasm-sha...

[3]: https://github.com/hsfzxjy/Bad-Apple-Font

>>cs702+(OP)
Related ongoing thread:

Tetris Font - >>40737294