Unexpected…

square.geo
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			// Mesh size
			h = 1; // Top cube

			// Dimensions of top cube
			Lx = 1;
			Ly = 1;

			// ------------------------------------------
			// Geometry
			// ------------------------------------------

			// Base Cube
			Point(101) = { 0.0, 0.0, 0.0, h}; // Bottom Face
			Point(102) = { Lx, 0.0, 0.0, h}; // Bottom Face
			Point(103) = { Lx, Ly, 0.0, h}; // Bottom Face
			Point(104) = { 0.0, Ly, 0.0, h}; // Bottom Face

			// Base Cube
			Line(101) = {101,102}; // Bottom Face
			Line(102) = {102,103}; // Bottom Face
			Line(103) = {103,104}; // Bottom Face
			Line(104) = {104,101}; // Bottom Face

			// Base Cube
			Line Loop(101) = {101:104};

			// Base Cube
			Plane Surface(101) = {101};
			Transfinite Surface {101};
			Transfinite Line {103, 101} = 10 Using Progression 1;
			Transfinite Line {104, 102} = 10 Using Progression 1;