%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 6-7-15 on page 426.
%% 
%%  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{ttctexagray}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{207.83385pt}
\StartShownPreambleCommands
\usepackage{pstricks,pst-eucl}
\StopShownPreambleCommands
\begin{document}
\psset{unit=1.5}
\begin{pspicture}(-2.5,-1.75)(2.75,2.5)
\pstTriangle[PosAngleA=180, PosAngleC=0](-2,-1){A}(1,2){B}(2,-1){C}
{ \psset{linestyle=none, PointSymbolB=none}
  \pstMediatorAB{B}{A}{I}{IP}
  \pstMediatorAB[PosAngleA=-40]{A}{C}{J}{JP}
  \pstMediatorAB[PosAngleA=75]{B}{C}{K}{KP}   }
\pstInterLL[PointSymbol=square, PosAngle=-170]{I}{IP}{J}{JP}{O}
{ \psset{nodesep=-.8,linecolor=green}
  \pstLineAB{O}{I}\pstLineAB{O}{J}\pstLineAB{O}{K} }
\psdot[dotstyle=square](O)
\pstProjection[PosAngle=95]{B}{A}{C}{C'}\pstProjection{B}{C}{A}{A'}
\pstProjection[PosAngle=-90]{A}{C}{B}{B'}
\psset{linecolor=blue}\ncline{A}{A'}\ncline{C}{C'}\ncline{B}{B'}
\pstInterLL[PointSymbol=square]{A}{A'}{B}{B'}{H}
\psset{linecolor=magenta}\ncline{A}{K}\ncline{C}{I}\ncline{B}{J}
\pstMiddleAB[PointSymbol=o, PointName=\omega]{O}{H}{omega}
\pstCircleOA[linecolor=cyan, linestyle=dashed, dash=5mm 1mm]{omega}{B'}
\empty
\psset{PointName=none}
\pstMiddleAB{H}{A}{AH}\pstMiddleAB{H}{B}{BH}\pstMiddleAB{H}{C}{CH}
\pstSegmentMark{H}{AH}\pstSegmentMark{AH}{A}
\psset{SegmentSymbol=wedge}\pstSegmentMark{H}{BH}\pstSegmentMark{BH}{B}
\psset{SegmentSymbol=cup}\pstSegmentMark{H}{CH}\pstSegmentMark{CH}{C}
\end{pspicture}
\end{document}