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
It reminds me of the way that speedruns and game replays are saved as deterministic timings of inputs -- almost like DOOM demofiles, except much more reasonable to track.
I like your idea of a Gameboy Emulator! Game of Life also feels like it would be possible in this structure, but I think Tetris is absolutely perfect. Top notch!!
What's the easiest way to play with this ourselves? Would be great if this font could be loaded on a webpage for us to play with interactively, but not sure how difficult that would be.
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...