%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 7-4-27 on page 498.
%% 
%%  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}
\StartShownPreambleCommands
\usepackage[all,poly]{xy}
\StopShownPreambleCommands
\begin{document}
\[\begin{xy}/r9mm/:
  (0,0),{\xypolygon6{%
   ~:{(1,-.1):(0,.33)::}~<{-}}}
 ,(0,2),{\xypolygon6{%
   ~:{(1,-.2):(0,.5)::}~<{-}}}
 ,(2.5,0),{\xypolygon6{%
   ~:{(1,.2):(0,-.3)::}~<{-}}}
 ,(2.5,2),{\xypolygon6{%
   ~:{(1,.3):(0,-.6)::}~<{-}}}
 ,(5,0)="O", +(-.5,3)="T","O"
 ,{\xypolygon6{~:{(1,0.2):(0,.4)::}
   ~<>{;"T"**@{-}}}}
\end{xy}\]
\end{document}