Source : Symetriqueangle.mp

input geometriesyr16;
vues:=19;
pair A,B,E,C,D,M[],N[];
A=u*(1,2);
B=u*(2,6);
E=u*(4,3);
C=u*(6,1);
D=u*(5,6);
for k=0 upto vues:
  figure(0,0,11u,8u);
  path an;
  an=chemin(1.2[A,B],A,1.25[A,E]);
  if k<11:
    M[k]=point((k/10)*length segment(1.2[A,B],A)) of segment(1.2[A,B],A)
  else:
    M[k]=point((k/vues)*length an) of an
  fi;
  N[k]=symetrie(M[k],C,D);
  path d;
  d=droite(C,D);
  trace d;
  label.rt(btex $(d)$ etex,C);
  trace an;
  marque_p:="croix";
  pointe(A,B,E);
  marque_p:="plein";
  for j=0 upto (k-1):
    pointe(M[j],N[j]);
  endfor;
  drawoptions(withcolor rouge);
  pointe(M[k],N[k]);
  drawoptions();
  trace perpendiculaire(C,D,M[k]) dashed evenly;
  trace codeperp(M[k],iso(M[k],N[k]),C,8);
  trace coupdecompas(iso(M[k],N[k]),M[k],10);
  trace coupdecompas(iso(M[k],N[k]),N[k],10);
  trace codesegments(M[k],iso(M[k],N[k]),iso(M[k],N[k]),N[k],2);
  marque_p:="non";
  nomme.llft(A);
  nomme.ulft(B);
  nomme.bot(E);
  fin;
endfor;
end