%% The LaTeX Graphics Companion, 2ed (first printing May 2007)

%%
%% 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}