COMMENT ⊗   VALID 00004 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	%\read16 to\pagenumber
C00003 00003	\ddanger Let's begin by recapping some of the rules at the end of Chapter~15.
C00005 00004	% now we print the answers, if any
C00006 ENDMK
C⊗;
%\read16 to\pagenumber
\input manmac
\tenpoint
\pageno=800
%\pageno=\pagenumber
\def\rhead{Experimental Pages for The \TeX book}
\def\chapno{ X}
{\catcode`\%=12 \immediate\write\ans{% Answers for galley proofs:}}
\ddanger Let's begin by recapping some of the rules at the end of Chapter~15.
\TeX\ periodically chooses to output a page of information, by breaking
its main vertical list at what it thinks is the best place, and at such times
it enters internal vertical mode and begins to read the commands in the
current |\output| routine. When the output routine begins, ↑|\box255|
contains the page that \TeX\ has completed; the output routine is supposed to
do something with this vbox. When the output routine ends, the list of
items that it has constructed in internal vertical mode is placed just
before the material that follows the page break. In this way \TeX's
page-break decisions can effectively be changed: Some or all of the material
on the broken-off page can be removed and carried forward to the next page.

\bye
% now we print the answers, if any

% that blank line will stop an unfinished \answer
\immediate\closeout\ans
\vfill\eject
\ninepoint
\input answers
\bye