extrude a surface mesh coming from an extruded line mesh...

benchmarks/extrude/Forma_3DCube.geo

+Rext = 0.2 ;
+Ep   = 0.02 ;
+Rint = Rext - Ep;
+RC   = 0.6     ;
+LG   = 3.0    ;
+
+h = 0.008;
+
+Point(1) = {Rext, 0, 0, h};
+Point(2) = {Rint, 0, 0, h};
+
+
+Line(1) = {1,2};
+
+Extrude Line {1,{0,1,0}, {0,0,0}, -Pi/2}
+             {Layers{10,5,1}; Recombine; };
+
+Extrude Line {2,{0,1,0}, {0,0,0}, -Pi/2}
+             {Layers{10,9,1}; Recombine; };
+
+
+Coherence;
+
+Extrude Surface {5,{0,LG,0}}
+                {Layers{50,2,1}; Recombine;  };
+
+
+Extrude Surface {9,{0,LG,0}}
+                {Layers{50,2,1}; Recombine;  };
+
+
+
+Extrude Surface {31,{0,0,1}, {RC,LG,0}, -(Pi/2)}
+                {Recombine ; Layers {30,52000,1}; };
+Extrude Surface {53,{0,0,1}, {RC,LG,0}, -(Pi/2)}
+                {Recombine ; Layers {30,530000,1}; };
+
+Extrude Surface {75,{LG,0,0}}
+                {Recombine; Layers{50,540000,1}; };
+Extrude Surface {97,{LG,0,0}}
+                {Recombine; Layers{50,550000,1}; };
+