- Space: Needs checking.
- SpecialChar: Needs checking.
- Split: There are some alignment issues here, but it basically works.
- - Substack: This is a stack of however many cells, all in a smaller style.
- Probably do something with <mover>, again.
- Tabular: This is more or less a text-like table in math. Probably output it
as a table, but set the font.