diff --git a/demos/piece-extr.geo b/demos/piece-extr.geo
new file mode 100644
index 0000000000000000000000000000000000000000..070e28da60f043c0863f0fbf1916912e9652bd5e
--- /dev/null
+++ b/demos/piece-extr.geo
@@ -0,0 +1,96 @@
+/* 
+   Gmsh demo file (C) 2000 C. Geuzaine, J.-F. Remacle
+*/
+
+r1 = .1;
+l1 = 1.;
+l2 = .8;
+l3 = .1;
+r2 = 1.1;
+lc = .1;
+lc2 = .05;
+rint = .2;
+rext = .3;
+
+Point(1) = {0.0,0.0,0.0,lc};
+Point(2) = {l1,0.0,0.0,lc2};
+Point(3) = {l1-r1,0.0,0.0,lc2};
+Point(4) = {l1,r1,0.0,lc2};
+Point(5) = {l1,-r1,0.0,lc2};
+Point(6) = {l1+l2,r1,0.0,lc};
+Point(7) = {l1+l2,-r1,0.0,lc};
+Point(8) = {l1+l2,-r1-l3,0.0,lc};
+Point(9) = {l1+l2,r1+l3,0.0,lc};
+
+Line(1) = {4,6};
+Line(2) = {6,9};
+Line(3) = {7,8};
+Line(4) = {5,7};
+Circle(5) = {4,2,3};
+Circle(6) = {3,2,5};
+
+r = 2*3.14159/5;
+Point(10) = { (l1 + r2) * Cos(r/2) , (l1 + r2) * Sin(r/2), 0.0, lc};
+
+// Remember, all rotations are specified by the axis direction
+// ({0,0,1}), an axis point ({0,0,0}) and a rotation angle (r)
+
+i = 0 ;
+
+For(1:4)
+
+  i+=1 ; 
+
+  Rotate {{0.0,0.0,1.0},{0.0,0.0,0.0}, i*r} {
+    Duplicata {
+      Line{1}; Line{2}; Line{3}; 
+      Line{4}; Line{5}; Line{6}; 
+      Point{10};
+    }
+  }
+
+EndFor
+
+Point(newp) = {rint,0,0,lc};
+Point(newp) = {rext,0,0,lc};
+Point(newp) = {-rint,0,0,lc};
+Point(newp) = {-rext,0,0,lc};
+Point(newp) = {0,rint,0,lc};
+Point(newp) = {0,rext,0,lc};
+Point(newp) = {0,-rint,0,lc};
+Point(newp) = {0,-rext,0,lc};
+
+Circle(31) = {8,118,97};
+Circle(32) = {20,10,9};
+Circle(33) = {47,37,16};
+Circle(34) = {74,64,43};
+Circle(35) = {101,91,70};
+Circle(36) = {119,1,123};
+Circle(37) = {123,1,121};
+Circle(38) = {121,1,125};
+Circle(39) = {125,1,119};
+Circle(40) = {124,1,122};
+Circle(41) = {122,1,126};
+Circle(42) = {126,1,120};
+Circle(43) = {120,1,124};
+
+Line Loop(44) = {37,38,39,36};
+Line Loop(46) = {40,41,42,43};
+Plane Surface(47) = {46,44};
+
+Line Loop(48) = {-2,-1,5,6,4,3,31,-26,-25,29,30,28,27,35,-20,-19,
+  23,24,22,21,34,-14,-13,17,18,16,15,33,-8,-7,11,12,10,9,32};
+Plane Surface(49) = {48,46};
+
+ones[]={1,1,1,1,1,1,1,1,1,1};
+ep[]={0.01, 0.05, 0.1, 0.2, 0.5, 0.8, 0.9, 0.95, 0.99, 1};
+For i In {0:4}
+  ep2[i]=2*ep[i]; 
+EndFor
+
+Extrude Surface {47, {0,0,0.2}}{ Layers{ ones[], ones[], ep[] }; };
+Extrude Surface {49, {0,0,0.2}}{ Layers{ ones[], ones[], ep[] }; };
+Extrude Surface {91, {0,0,0.2}}{ Layers{ ones[{0:4}],ones[{0:4}], ep2[] }; };
+Extrude Surface {47, {0,0,-0.2}}{ Layers{ ones[{0:4}],ones[{0:4}], ep2[] }; }; 
+
+Physical Volume(1) = 1 ;