\expandafter\xdef\csname c@tcode\endcsname{\the\catcode`\@}
\catcode`\@=11
%
\parindent=0pt 
\parskip=\baselineskip
%
\def\SetNumber#1{\def\Pr@blemSet{#1}}
\def\Course#1{\def\C@urse{#1}}
\def\MyName#1{\def\MyN@me{#1}}
\MyName{Andrew Marc Greene}
%
\newif\ifm@kerule
%
\let\ea\expandafter
\ea\ea\ea\ea\ea\ea\ea\everypar\ea\ea\ea{\ea\m@keruletrue\the\everypar}
%
\def\header{Massachusetts Institute of Technology \hfil 
Problem Set \Pr@blemSet\break
\C@urse \hfil \MyN@me\vadjust{\vskip 1pt\hrule}\break\par\m@kerulefalse}
%
\def\problem#1#2{\ifm@kerule\bigskip\hrule\bigskip\else\m@keruletrue\fi
{\bf Problem #1: \sl #2}\par}
\def\book#1#2{{\sc Problem #1; P. #2}\par}
%
\catcode`\@=\c@tcode
