[solved] plain TeX: different margins for odd and even pages

[Rodolfo Medina]

"Philip Taylor (Hellenic Institute)" <elliniko.institouto at gmail.com> writes:

> On 25/10/2025 22:55, Rodolfo Medina wrote:
>
>  In `pure' plain TeX, for me it also works with, more simply: 
>
> \hoffset=-1in
> \voffset=-1in
> \special{papersize=420mm,297mm}
> \hsize=365 true mm
> \vsize=297 true mm
> \advance\voffset by5mm
> \advance\vsize by-10mm
> \newtoks \Knuthput
> \Knuthput = \output
> \output = {\ifodd \pageno \advance \hoffset by5mm \else \advance
> \hoffset by50mm \fi \the \Knuthput}
>
> Yes, if you prefer to eschew e-TeX's \<whatever>expr primitives, that is
> indeed a valid solution.  Well done Rodolfo.


I only just but slightly simplified a little bit your solution...

Thanks,

Rodolfo