   /* Rectangle Geometry File */

    gridsize = 2.0; // prescribed mesh element size
    
    Lx = 10.0; // width
    Ly = 10.0;   // height
    
    Point(1) = {0, 0, 0, gridsize};
    Point(2) = {0, Ly, 0, gridsize};
    Point(3) = {Lx, Ly, 0, gridsize};
    Point(4) = {Lx, 0, 0, gridsize};
 
    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};

    //Transfinite Line{1} = 10 Using Progression 1;
    //Transfinite Line{2} = 10 Using Progression 1;
    //Transfinite Line{3} = 10 Using Progression 1;
    //Transfinite Line{4} = 10 Using Progression 1;
    //Transfinite Surface{6} = {1,2,3,4};
    //Recombine Surface {6};
    
    Periodic Line {1} = {3};
    Periodic Line {2} = {4};
