%%
%% The LaTeX Companion, 3ed
%%
%% Example 5-2-9 on page I-383 in "geometry --- Layout specification with auto-completion".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{102.60104pt}
%
  \usepackage{layouts}
  \newcommand\showpage{%
    \setlayoutscale{0.27}%
    \setlabelfont{\tiny}%
    \printheadingsfalse
    \printparametersfalse
    \currentpage\pagedesign}

%StartShownPreambleCommands
\usepackage[a6paper,twoside]{geometry}

%StopShownPreambleCommands

\begin{document}
% \showpage as previously defined

\showpage
\newgeometry{rmargin=5pt,bmargin=2in,
             includemp}
\showpage

\end{document}