This is a horrible, horrible hack and it's terrifying and I am aghast at how amazing this is. Such a wonderful abuse of OpenType contextual alternatives. Well done and thank you for sharing!!
What makes it a horrible hack, as opposed to proper use of documented capabilities at a scale slightly larger than usual?
Putting animated SVG in a font [1] is a horrible hack; this one is benign.
A somehow larger stretch would be a font with a built-in spell checker, with a wavy underline under every letter that only disappears under correctly spelled words.
"Putting animated SVG in a font [1] is a horrible hack"
Agreed, that is even more horrible. And probably just for performance reason alone should never ever get close to a real world product. Still, quite neat.
