%!PS-Adobe-3.0 EPSF-3.0
%%BoundingBox:   53   75  335  356
335 % third BoundingBox parameter
 53 % first BoundingBox parameter
sub 4 div
80 % width in mm specified in \includegraphics
div /myscale exch def

myscale setlinewidth newpath
  243  340 moveto
   72  340 lineto
   72  108 lineto
  320  108 lineto
   72  225 lineto
stroke
   72  108 moveto
  211  340 lineto

   72  340 moveto
  243  108 lineto

  196  108 moveto
  178  340 lineto

  320  108 moveto
  182  291 lineto

  119   80 moveto
  259   80 lineto
stroke

/Helvetica findfont 16 myscale mul scalefont setfont
  320   94 moveto (a) show
  191  288 moveto (b) show
   58  103 moveto (c) show
   60  342 moveto (d) show
  127  183 moveto (e) show
   63  220 moveto (f) show
  212  326 moveto (g) show
  194   94 moveto (h) show
  156  234 moveto (k) show
  170  342 moveto (l) show
  100   78 moveto (m) show
  264   78 moveto (n) show
  241   94 moveto (p) show