%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 7-4-3 on page 480.
%% 
%%  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{183.83385pt}
\StartShownPreambleCommands
\usepackage[arrow]{xy}
\StopShownPreambleCommands
\begin{document}
\[\begin{xy} <6mm,0mm>:
  (0,0)*+\txt\small{Origin}="O"
  \ar@{.>>}
    `r  (3,2) *\dir{*}*+!DL{\mathrm{P_1}} ^-1
    `   (-2,2)*\dir{*}*+!U{\mathrm{P_2}}  ^2
    `_dr(-2,0)*\dir{*}*+!U{\mathrm{P_3}}  _(.3)3
    `dr^r "O"                             _(.8)4
          "O"                             ^-(.2)5
\end{xy}\]
\end{document}