manual…

square_structured.geo
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			// Gmsh project created on Wed Dec 8 09:32:40 2010
			lc = 0.4;
			Point(1) = {0, 0, 0, lc};
			Point(2) = {1, 0, 0, lc};
			Point(3) = {1, 1, 0, lc};
			Point(4) = {0, 1, 0, lc};
			Line(1) = {1, 2};
			Line(2) = {2, 3};
			Line(3) = {3, 4};
			Line(4) = {4, 1};
			Line Loop(5) = {3, 4, 1, 2};
			Plane Surface(6) = {5};
			Transfinite Surface "*";
			Recombine Surface "*";

			Mesh.SecondOrderIncomplete = 1;