Glyphs

# (find-vtutil4 "")
# (find-vtutil4 "README")
# (find-vtutil4 "mathchars.lua")
# (find-vtutil4 "Makefile")

• vtutil4 (and its ancestor, vtutil) let us replace some characters of a console font by mathematical symbols.
• For something related that works on X, see this posting in the eev mailing list. Source files: eev-glyphs.el, eev-math-glyphs.el.
• A preprocessor for (La)TeX for typesetting categorical diagrams and deduction trees: dednat4. Its ancestors, like dednat.lua, supported only deduction trees; the first version was this one-hour hack written in Icon (I don't understand its code anymore).