Making the left-hand side of a double spread always print the same within part of a document

Question

I wish to print the actual running text* of part of a document only on the right-hand side pages of double spreads, while the left-hand side repeats the same every time because the reader will want to be able to refer to the information on the left-hand page frequently while reading the right-hand side, without having to flip the pages back and forth.

Here’s a mocked-up layout example of what I’d like:

How can I achieve this with LaTeX or LuaTeX? (I’m using the book document class, if that makes a difference.)

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* Detail: it’s not actually running text but a Gregorio score, but hopefully that doesn’t make too much difference given that Gregorio, to my knowledge, uses the normal text and block and page wrapping of TeX.

Answer 1

You could override the \shipout primitive in LuaTeX. To get the correct margins, headers, and footers, a bit more work is required.

\documentclass{article}
\usepackage{pgffor}

\newbox\infobox

% Override the shipout primitive to also shipout infobox
\def\shipout{\directlua{
    local box = token.scan_list()
    tex.setbox(255, box)
    tex.shipout(255)
    tex.setbox(255, node.copy(tex.getbox("infobox")))
    tex.shipout(255)
}}

\begin{document}

% Set infobox only after \begin{document}.  Otherwise fonts will not
%   be loaded.
\setbox\infobox=\vbox to \textheight{
  \vfill
  \Huge\input ward\par
  \vfill
}

\foreach \i in {1,...,20} {
  \input knuth\par
}

\end{document}