He was dismayed at the declining quality of mathematical typesetting, so he took some time to create his own system. https://en.wikipedia.org/wiki/TeX https://

He was dismayed at the declining quality of mathematical typesetting, so he took some time to create his own system. https://en.wikipedia.org/wiki/TeX https://en.wikipedia.org/wiki/TeX https://en.wikipedia.org/wiki/Metafont https://en.wikipedia.org/wiki/Metafont