\documentclass[a4paper,landscape]{book}

\usepackage{config/bind}

\externalReferent{core}

\settoggle{verbose}{false}
\settoggle{genExamples}{false}

\newtoggle{upsideDown}
\settoggle{upsideDown}{true}

\renewcommand\subsubsection[1]{{\noindent\Large\scshape #1}}
\renewcommand{\labelitemi}{\tiny ---}
%\setlength{\leftmargin}{-3em}
\setlength{\labelsep}{.5em}
\setlength{\itemindent}{0.5em}
\setlength{\columnsep}{1em}
\parindent1em
\setcounter{pageDarkness}{50}
\setlength{\columnseprule}{.2pt}
\renewcommand\hint[1]{\par
  \textit{#1}
}

\newcommand\showPage{%
  \iftoggle{countedPage}{
    \ifnum\thepage>12%
      \ifodd\thepage%
        \node at ([xshift=-2em]interior.south east) {\thepage} ;%
      \else%
        \node at ([xshift=2em]interior.south west) {\thepage} ;%
      \fi%
    \else%
      \ifnum\thepage<6%
        \ifodd\thepage%
          \node at ([xshift=-2em]interior.south east) {\thepage} ;%
        \else%
          \node at ([xshift=2em]interior.south west) {\thepage} ;%
        \fi%
      \else%
        \ifodd\thepage%
          \node[rotate=180] at ([xshift=24em]interior.south) {\thepage} ;%
        \else%
          \node[rotate=-180] at ([xshift=2em]interior.south west) {\thepage} ;%
        \fi%
      \fi%
    \fi%
  }{}%
}

\pagestyle{empty}

\tcbset{reset}
\begin{document}
\input{fold_front.tex}
\input{fold_back.tex}

\end{document}
