%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 8-4-18 on page 570.
%% 
%%  Copyright (C) 2007 Michel Goossens, Frank Mittelbach, Denis Roegel, Sebastian Rahtz, Herbert Vo\ss 
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 

\documentclass{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{207.83385pt}
\AtEndDocument{\end{fmffile}}
  \AtBeginDocument{\begin{fmffile}{ftmp}}
\StartShownPreambleCommands
\usepackage{feynmp}
\StopShownPreambleCommands
\begin{document}
\fbox{\begin{fmfgraph}(100,40)
 \fmfleft{w}\fmfright{e}
 \fmf{boson}{w,vw}\fmf{boson}{ve,e}
 \fmf{fermion,tension=.5}{vw,vn,ve,vs,vw}
 \fmf{gluon}{vn,vs}
 \fmffixed{(0,h)}{vn,vs}
 \fmfdot{vw,vn,ve,vs}
\end{fmfgraph}}
\fbox{\begin{fmfgraph}(100,40)
 \fmfleft{w}\fmfright{e}
 \fmf{boson}{w,vw}\fmf{boson}{ve,e}
 \fmf{phantom,left,tension=.4}{vw,ve,vw}
 \fmfdot{vw,ve}
 \fmffreeze
 \fmfipath{pn,ps}\fmfipair{vn,vs}
 \fmfiequ{pn}{vpath (__vw, __ve)}
 \fmfiequ{ps}{vpath (__ve, __vw)}
 \fmfiequ{vn}{point .5length(pn) of pn}
 \fmfiequ{vs}{point .5length(ps) of ps}
 \fmfi{fermion}{subpath (0,.5)*length(pn) of pn}
 \fmfi{fermion}{subpath (.5,1)*length(pn) of pn}
 \fmfi{fermion}{subpath (0,.5)*length(ps) of ps}
 \fmfi{fermion}{subpath (.5,1)*length(ps) of ps}
 \fmfi{gluon}{vn--vs}
 \fmfiv{dec.sh=circle,dec.siz=2thick}{vn}
 \fmfiv{dec.sh=circle,dec.siz=2thick}{vs}
\end{fmfgraph}}
\end{document}
