prologues:=2;

verbatimtex
%&latex
\documentclass[12pt]{article}
\usepackage[charter]{mathdesign}
\usepackage{pifont}
\begin{document}
etex

input geometriesyr16
figure(0,0,10u,8u);
u:=8mm;
pair O,C,D,H,A,I,J,K,P;
O=u*(6,5);
path cc,cd,ce;
cc=cercles(O,2.75u);
P=pointarc(cc,75);
cd=cercles(O,5u);
A=pointarc(cd,48);
I=cc intersectionpoint segment(O,A);
ce=perpendiculaire(O,A,I);
J=cd intersectionpoint ce;
K=symetrie(J,O,A);
C=segment(O,J) intersectionpoint cc;
D=segment(O,K) intersectionpoint cc;
H=iso(C,D);
trace droite(O,O+u*(1,0)) dashed evenly;
trace droite(O,O+u*(0,1)) dashed evenly;
trace cc;
trace cd dashed withdots;
drawoptions(withcolor gris);
trace Codelongueur(C,H,H,D,2);
trace segment(C,D) dashed evenly;
trace chemin(J,O,K);
trace demidroite(A,C);
trace demidroite(A,D);
trace codeperp(O,C,A,5);
trace codeperp(O,D,A,5);
drawoptions();
nomme.llft(H);
label.urt(btex Observateur etex,A);
nomme.llft(O);
nomme.urt(P);
drawarrow segment(H,P) withpen pencircle scaled1.5bp;
drawarrow segment(H,A) withpen pencircle scaled1.5bp;
fin;
end