/usr/share/doc/texlive-doc/plain/graphics-pln/exmplpic.tex is in texlive-plain-extra 2014.20141024-1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 | \input picture
\picture(100,100)
\put(0,0){\line(1,1){50}}
\endpicture
\LaTeXbegin
\begin{picture}(40,40)
\put(0,0){\vector(1,1){40}}
\multiput(0,5)(10,10){4}{a}
\end{picture}
\bye
|