% Read in by FEYNMANDOC:  FEYNMANDOC3D.  Called by FD3D.COM
\begin{picture}(30000,15000)
\drawvertex\gluon[\E 4](15000,0)[3]
\drawline\fermion[\SW\REG](\vertexonex,\vertexoney)[\vertextwoy]
\flipvertex\drawvertex\gluon[\E 4](\vertexthreex,\vertexthreey)[3]
\drawvertex\gluon[\N 4](\vertextwox,\vertextwoy)[3]
\flipvertex\drawvertex\gluon[\W 4](\vertextwox,\vertextwoy)[3]
\drawline\fermion[\NW\REG](\vertexthreex,\vertexthreey)[\fermionlength]
\drawline\fermion[\S\REG](\vertexthreex,\vertexthreey)[\vertexthreey]
%%%%  TEX CAPACITY EXCEEDED %%%
%\vertexlink3
%\drawvertex\gluon[\N 3](\vertexfourx,\vertexfoury)[4]
%\drawvertex\gluon[\NE 4](\vertexthreex,\vertexthreey)[3]
%\drawline\fermion[\E\REG](\vertexthreex,\vertexthreey)[2000]
%\drawline\fermion[\N\REG](\vertexthreex,\vertexthreey)[2000]
\end{picture}

\vskip 0.72in
Of note here are the lengths used for the fermions.  Since the first
vertex is drawn with ordinate $y=0$, \bs vertextwoy will be
the length of each gluon arm.  Thus the lower exterior
fermion will also be of this length.  The upper fermion is of
length \bs fermionlength, that is the length of the previously drawn
fermion, assuring a match.  The final fermion line is drawn from the
specified point to $y=0$ using the same trick as above.

An unfortunate defect of \FEYNMAN\ may be noticed by returning to 
the three-gluon vertices on the previous page.  Occasionally
one might wish to attach the upper left example onto the 
Eastern line of the lower right example.  This would lead to
a gluon of \bs FLIPPEDCURLY (\ie\ a non-central style) being joined
with a \bs CENTRAL gluon configuration.  This cannot be accomplished
smoothly without employing arcane tricks usually involving some effort.
% TO SEE HOW LOOK AT FILE VERTEST23.TEX, VERTEST24.TEX
Similar comments can be made concerning certain combinations of three- and 
four-gluon vertices.

Vertices may also be linked, capped and stemmed, as will be discussed in
the next chapter.  Examples of these features were given in
section 2.10.2.  Also in that section was a diagram labelled ``gluonburst''.
We conclude this chapter by re-creating this using two \ddrawvertex\ commands.
The reproduction of this diagram is an exercise for the section on
placement of information in chapter four.
In parting a brief word  of caution about \TeX's memory usage.  In the section 
on gluon lines it was pointed out that gluons consume vast portions of
\LaTeX's 65500 words of internal memory (only 40000 of which is available to
the user).  
This is trebly true for gluon
vertices.  Extending the vertices on the following page by two loops per
line requires an additional 10000 words.  In point of fact this one sample
diagram uses 99\% of the available memory!  For this reason it has been
drawn slightly smaller than the example in chapter 2.
