\input tex
\letter
\input ruled
\font\rm=cmbx12 scaled\magstep2
\rm
%\hfuzz=20pt
\def\bs{\baselineskip20pt}
\def\bigstrut{\vrule height.60in depth.60in width0in}
\def\tstrut{\vrule height28pt depth 8pt width 0in}
\thicksize=3pt
\thinsize=3pt
\parasize=1.4in
\tablewidth=4in

\baselineskip=20pt
The following `table of behavior' completely defines a machine with the 
character of an adding machine. Starting with the `scanner' somewhere to
the left of two groups of 1's, separated by a single blank space, it will
add the two groups and stop. Thus it will transform

\bigskip

{\raggedright
\begintable
\bigstrut |  {\vctr{\quad blank}\hfill}|  {\vctr{\quad 1}\hfill} \cr
\bigstrut\vctr{Config.~1}| \vctr{\para{\bs move right;\goodbreak config.~1}}| \vctr{\para{\bs move right;\goodbreak config.~2}} \cr
\bigstrut\vctr{Config.~2}| \vctr{\para{\bs write 1;\goodbreak move right;\goodbreak config.~3}}| \vctr{\para{\bs move right;\goodbreak config.~2}} \cr
\bigstrut\vctr{Config.~3}| \vctr{\para{\bs move left;\goodbreak config.~4}}| \vctr{\para{\bs move right;\goodbreak config.~3}} \cr
\bigstrut\vctr{Config.~4}| \vctr{\para{\bs no move;\goodbreak config.~4}}| \vctr{\para{\bs erase;\goodbreak no move;\goodbreak config.~4}}\endtable
}

\bigskip

into

\bye