<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">\message{double column macros from the TeXbook}
\def\makeheadline{\vbox to 0pt{\vskip-22.5pt
   \fullline{\vbox to 8.5pt{}\the\headline}\vss}\nointerlineskip}
\def\makefootline{\baselineskip=24pt \fullline{\the\footline}}
\newdimen\fullhsize
\fullhsize=6.5in \hsize=3.1in
\def\fullline{\hbox to\fullhsize}
\let\lr=L \newbox\leftcolumn
\output={\if L\lr
    \global\setbox\leftcolumn=\columnbox \global\let\lr=R
          \else
     \doubleformat \global\let\lr=L\fi
           \ifnum\outputpenalty&gt;-20000 \else\dosupereject\fi}
  \def\doubleformat{\shipout\vbox{\makeheadline
       \fullline{\box\leftcolumn\hfil\columnbox}
        \makefootline}
    \advancepageno}
  \def\columnbox{\leftline{\pagebody}}
</pre></body></html>