\input fop%
\shipout\hbox{\smash{\hbox{\hbox{% line 7 mbmac.mp
$-$}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 7 mbmac.mp
$1$}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 7 mbmac.mp
${\times}10$}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 8 mbmac.mp
${}^-$}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 8 mbmac.mp
${}^2$}\vrule width1sp}}}
\shipout\hbox{\smash{\hbox{\hbox{% line 9 mbmac.mp
$10$}\vrule width1sp}}}
\end{document}
