    n = 10.0;
    hloc = 1.0/n;
    Point(1) = {0, 0, 0, hloc};
    Point(2) = {1, 0, 0, hloc};
    Point(3) = {1, 1, 0, hloc};
    Point(4) = {0, 1, 0, hloc};
    Line(1) = {1,2};
    Line(2) = {2,3};
    Line(3) = {3,4};
    Line(4) = {4,1};
    Line Loop(5) = {1,2,3,4};
    Plane Surface(6) = {5} ;
    Physical Point("left_bottom")  = {1};
    Physical Point("right_bottom") = {2};
    Physical Point("right_top")    = {3};
    Physical Point("left_top")     = {4};
    Physical Line("boundary") = {1,2,3,4};
    Physical Line("bottom") = {1};
    Physical Line("right")  = {2};
    Physical Line("top")    = {3};
    Physical Line("left")   = {4};
    Physical Surface("interior") = {6};
