void geo2d_creer_rotation(double, double[2][3]);
void geo2d_creer_echelle(double, double[2][3]);
void geo2d_creer_translation(double, double, double[2][3]);
void geo2d_composer(double[2][3], double[2][3], double[2][3]);
void geo2d_appliquer(double[2][3], double[2]);