lc = 1e-1;
//Mesh.CharacteristicLengthFromPoints=1;
Lx = 1;
Ly = 1;

// Domain Points
Point(1) =  {0, 0, 0, lc};
Point(2) =  {Lx, 0,  0, lc};
Point(3) =  {Lx, Ly, 0, lc};
Point(4) =  {0, Ly, 0, lc};
//Interface points
Point(5) =  {0, 0.5, 0, lc};
Point(6) =  {0.5, 1, 0, lc};
Point(7) =  {1, 0.5, 0, lc};

// Domain Line
Line(1) =  {1, 2};       
Line(2) =  {2, 3};
Line(3) =  {3, 4};
Line(4) =  {4, 1};
// Interface line
Line(5) =  {5, 6};
Line(6) =  {6, 7};
// interfaceLabel = [5, 6] //OUTPUT

Line Loop(1) =  {1, 2, 3, 4};

Plane Surface(1) =  {1};

//To create a structured mesh (with quadrangle)
//Transfinite Line{1,2,3,4} = 10;
//Transfinite Surface {1} = {1,2,3,4};
//Recombine Surface {1};


