The following LaTeX document does an evil hofstadterian trick with page references such that the references are always wrong.

In every compilation, the size of the \pageref output moves the \label to another page. Thus, compiling the input file many times always gives the same message:

LaTeX Warning: Label(s) may have changed. Rerun to get cross-references right.

The key pages are 9-10 and 99-100.

%% begin document
\documentclass[10pt,a4paper]{article}
\newcommand{\op}{
0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\
0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\
0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\}
\newcommand{\tp}{\op\op\op\op\op\op\op\op\op\op}

\begin{document}
\op\op\op\op\op\op\op\op
0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\
0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\
0\\1\\2\\3\\4\\5\\6\\7\\8\\
(\pageref{X}) (\pageref{X}) (\pageref{X}) (\pageref{X}) (\pageref{X}) (\pageref{X})
(\pageref{X}) (\pageref{X}) (\pageref{X}) (\pageref{X}) (\pageref{X}) (\pageref{X})
(\pageref{X}) HERE: \label{Y} Y | just to fill some space\\
1\\2\\3\\4\\5\\6\\7\\8\\9\\0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\
0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\
0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\
\op\op\op\op\op\op\op\op\op\tp\tp\tp\tp\tp\tp\tp\op\op\op\op\op\op\op\op\op
0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\
0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\0\\1\\2\\3\\4\\5\\6\\7\\8\\9\\
0\\1\\2\\3\\4\\5\\6\\7\\8\\
(\pageref{Y}) (\pageref{Y}) (\pageref{Y}) (\pageref{Y}) (\pageref{Y}) (\pageref{Y})
(\pageref{Y}) (\pageref{Y}) (\pageref{Y}) (\pageref{Y}) (\pageref{Y}) (\pageref{Y})
(\pageref{Y}) (\pageref{Y}) (\pageref{Y}) (\pageref{Y}) HERE: \label{X} X
\end{document}
changed December 5, 2007