I can't imagine a situation where this would matter for plain text. I suppose one could use the ECMA-48 / ISO 6429 SPD (Select Presentation Direction) control sequence, but that is hardly plain text, altho it isn't quite markup either.
- Re: vertical direction control Michael Everson
- Re: vertical direction control Philippe Verdy
- Re: vertical direction control Peter Kirk
- Re: vertical direction control Michael Everson
- Re: vertical direction control Chris Jacobs
- Re: vertical direction control Stefan Persson
- Re: vertical direction control Peter Kirk
- Re: vertical direction control Timothy Partridge
- RE: vertical direction control Mike Ayers
- Re: vertical direction control Stefan Persson
- Re: vertical direction control Ernest Cline
- Re: vertical direction control Thomas Kuehne
- RE: vertical direction control jarkko.hietaniemi
- RE: vertical direction control Peter Constable
- RE: vertical direction control Peter Constable
- Re: vertical direction control Peter Kirk
- RE: vertical direction control Ernest Cline
- RE: vertical direction control Peter Constable
- RE: vertical direction control Michael Everson
- RE: vertical direction control Ernest Cline
- RE: vertical direction control Michael Everson