\psset{linewidth=1.2\pslinewidth}\renewcommand{\NbPt}{11}
\pstGeonode[PosAngle={0,-90}](5,4){O}(1,2){A}(9,1.5){B}
\newcommand{\Parabole}[1][100]{%
  \pstLineAB[nodesep=-.9, linecolor=green]{A}{B}
  \psset{RotAngle=90, PointSymbol=none, PointName=none}
  \multido{\n=1+1}{\NbPt}{%
    \pstHomO[HomCoef=\n\space \NbPt\space 1 add div]{A}{B}[M\n]
    \pstMediatorAB[linestyle=none]{M\n}{O}{M\n_I}{M\n_IP}
    \pstRotation{M\n}{A}[M\n_P]
    \pstInterLL[PointSymbol=square, PointName=none]{M\n_I}{M\n_IP}{M\n}{M\n_P}{P_\n}
    \ifnum\n=#1
      \bgroup
      \pstRightAngle{A}{M\n}{M\n_P}
      \psset{linewidth=.5\pslinewidth, nodesep=-1, linecolor=blue}
      \pstLineAB{M\n_I}{P_\n}\pstLineAB{M\n}{P_\n}
      \pstRightAngle{P_\n}{M\n_I}{M\n}
      \psset{linecolor=red}\pstSegmentMark{M\n}{M\n_I}\pstSegmentMark{M\n_I}{O}
      \egroup
    \fi}}%fin multido-newcommand
\Parabole[2]\pstGenericCurve[linecolor=magenta]{P_}{1}{\NbPt}
%% Nouvelle parabole avec un nouveau point B
\pstGeonode[PointSymbol=*, PosAngle=-90](10,3.5){B}
\psset{linestyle=dashed}
\Parabole\pstGenericCurve[linecolor=magenta]{P_}{1}{\NbPt}
