The object \Lkeyword{rightangle} allows us to specify and draw a
\Index{right angle}. The syntax is: \texttt{[object=rightangle,args=$A$
$B$ $C$]}
\begin{LTXexample}[width=7.5cm]
\begin{pspicture}(-3,-2.5)(3.5,2.5)%
\psframe*[linecolor=blue!50](-3,-2.5)(3.5,2.5)
\psset{lightsrc=viewpoint,viewpoint=50 30 15,Decran=40}
\psset{solidmemory}
%% definition du plan de projection
\psSolid[object=plan,
definition=equation,
args={[1 0 1 0] 90},
base=-4 4 -3 3,
fillcolor=white,
linecolor=gray!30,
% plangrid,
planmarks,
name=monplan]
\psset{plan=monplan,visibility=false}
%% definition droite d
\psProjection[object=droite,
definition=horizontale,
args=-1,name=d]
\psset{fontsize=15}
%% definition du point M
\psProjection[object=point,
args=-2 1,
name=M,text=M,
pos=ul]
%% definition du point H
\psProjection[object=point,
definition=orthoproj,
args=M d,
name=H,text=H,
pos=dr]
%% definition du point H' pour orienter l'angle droit
%% et mettre la legende
\psProjection[object=point,
definition=xdpoint,
args=2 d,name=H',
action=none,
text=d,pos=ur]
%% definition d'une ligne
\psProjection[object=line,
args=M H]
%% dessin angle droit
\psProjection[object=rightangle,
args=M H H']
\composeSolid
%\axesIIID(4,4,2)(5,5,6)
\end{pspicture}
\end{LTXexample}
