	Diam=.12;
	Ext=.25;
	lce=Diam/6;
	xc=0;
	yc=0;
	zc=.25;
	REl=Diam/2/1.414;

	p = newp;  
	Point(p)  ={xc      , yc       , zc       , lce};
	Point(p+1)={xc-REl      , yc-REl       , zc       , lce};
	Point(p+2)={xc+REl      , yc-REl       , zc       , lce};
	Point(p+3)={xc+REl      , yc+REl       , zc       , lce};
	Point(p+4)={xc-REl      , yc+REl       , zc       , lce};

	c = newl;
	Circle(c)   = {p+1, p  ,p+2};
	Circle(c+1) = {p+2, p  ,p+3};
	Circle(c+2) = {p+3, p  ,p+4};
	Circle(c+3) = {p+4, p  ,p+1};
	ll = newll;
	Line Loop(ll) = {c,c+1,c+2,c+3};
	s = news;
	Plane Surface(s) = {ll};  //  
	
	tmp[] = Extrude  {0,0,-Ext} { Surface {s}; }; // extrusioon to build a cylinder

		VolE[] += tmp[1];
		sl=newsl;
		Skin_E[]= CombinedBoundary{Volume{VolE[]};};
		Surface Loop (sl) ={Skin_E[]};
		v = newv;
		Volume(v) = {sl};
		Skin_E[]-={s};                       // Substract   sl
											//  OK with gmsh version 2.8.4 on windows 7  64bits
											//  looks problematic  with gmsh version 3.0.5 on windows 7  64bits
		
		PVol= 10;
		PSurf= 1;
		
		Physical Volume(PVol) = {v};
		Physical Surface(PSurf) = {Skin_E[]}; // displayed with "tools" "visibility"
		Physical Surface(PSurf+1) = {s};
	
