    h_local = 0.1;
    Point(1) = {0, 0, 0, h_local};
    Point(2) = {1, 0, 0, h_local};
    Line(3) = {1,2};
    Physical Point("left")  = {1};
    Physical Point("right") = {2};
    Physical Point("boundary") = {1,2};
    Physical Line("interior") = {3};
