Point(1) = {-1, -1, 0};
Point(2) = {1, -1, 0};
Point(3) = {1, 1, 0};
Point(4) = {-1, 1, 0};
Line(1) = {1, 2};
Line(2) = {2, 3};
Line(3) = {3, 4};
Line(4) = {4, 1};
Line Loop(21) = {1, 2, 3, 4};

Plane Surface(22) = {21};

Transfinite Line {1, -3} = 3;
Transfinite Line {2, -4} = 4;
Transfinite Surface{22} = {};
Recombine Surface{22};

out[] =
Extrude {0, 0, 5} {
  Surface{22};
  Layers{2};
  Recombine;
};

Physical Volume(99) = out[1];
