\def\rms{\rm}
\def\its{\it}
\def\bfs{\bf}
\def\sss{\ss}
\def\sis{\si}
\def\fixaccent#1#2 {{\setbox0\hbox{#2}\ifdim\ht0=1ex\accent#1 #2%
  \else\ooalign{\unhbox0\crcr\hidewidth\char#1\hidewidth}\fi}}
\def\size[#1]{%
  \let\prevstyle\laststyle
  \baselineskip#1pt
  \baselineskip=1.2\baselineskip
  \def\rm{\font\thfa=cmr10 at#1pt\font\thfb=csr10 at#1pt\let\laststyle\rms\thfa}%
  \def\it{\font\thfa=cmti10 at#1pt\font\thfb=csti10 at#1pt\let\laststyle\its\thfa}%
  \def\bf{\font\thfa=cmbx10 at#1pt\font\thfb=csbx10 at#1pt\let\laststyle\bfs\thfa}%
  \def\ss{\font\thfa=cmss10 at#1pt\font\thfb=csss10 at#1pt\let\laststyle\sss\thfa}%
  \def\si{\font\thfa=cmssi10 at#1pt\font\thfb=csssi10 at#1pt\let\laststyle\sis\thfa}%
  \prevstyle
}\let\laststyle\rms
\size[10]\ss