% 1. Definition of characteristic points

\figinit{2cm}

% Demi-abscisse du point A.
\def\demia{0.6}
% Angle du point de tangence en haut.
\def\ang{48}
% Angle droit.
\def\Dim{.1}

% Point O
\figpt 1:(0,0)
% Centre Omega du cercle
\figpt 6:(\demia,0)
% Point A
\figptbary 2:[1,6;-1,2]
% Point B
\figptbary 3:[1,2;-1,2]
% Perpendiculaire a (OB) passant par B.
\figvectN 0 [1,3]
\figpttra 4:=3/.6,0/
\figpttra 5:=3/-.4,0/
% Perpendiculaire a (OB) passant par A.
\figvectP 0 [3,1]
\figptstra 12=4,5/1,0/
% Point de tangence en haut.
\figptrot 7:=2/6,\ang/
% Points d'intersection M2 et P.
\figvectN 0 [6,7]
\figvectN 100 [1,3]
\figptinterlines 8:[7,0;1,100]
\figptinterlines 9:[7,0;3,100]
% Point M1.
\figvectP 0 [3,9]
\figpttra 10:=8/1,0/
\figptrot 10:=10/1,180/
% Point R de tangence en bas.
\figvectN 0 [9,10]
\figvectP 100 [9,10]
\figptinterlines 11:[6,0;9,100]
%
\figvectP 0 [9,8]
\figpttra 14:=8/0.1,0/
\figvectP 0 [9,10]
\figpttra 15:=10/0.1,0/

% 2. Creation of the graphical file

\figdrawbegin{}

\figdrawline[4,5]
\figdrawaltitude \Dim[6,8,9]
\figdrawaltitude \Dim[6,10,9]
\figdrawaltitude \Dim[6,5,4]
\figdrawaltitude \Dim[6,13,12]
\figdrawline[14,9]
\figdrawline[15,9]
\figdrawline[12,13]
\figdrawcirc 6(\demia)

\figdrawend

% 3. Writing text on the figure

\def\disti{3pt}

\figvisu{\figBoxA}{Figure 4}{%
%\figshowpts[1,12]
\figwritesw 1:$O$(\disti)
\figwritese 2:$A$(\disti)
\figwritese 3:$B$(\disti)
\figwritenw 6:$\Omega$(\disti)
\figwritee 9:$P$(\disti)
\figwritesw 8:$M_{2}$(\disti)
\figwritesw 10:$M_{1}$(\disti)
}
\centerline{\box\figBoxA}