// model point definitions --------------
Point(1) =  {0.5, 0.0  , 0.0  } ;
Point(2) =  {0.5, 0.0  , 0.25 } ;
Point(3) =  {0.0, 0.0  , 0.25 } ;
Point(4) =  {0.0, 0.0  , 0.0  } ;
// line definitions and loop definitions-
Line(1) = {1, 2};
Line(2) = {2, 3};
Line(3) = {3, 4};
Line(4) = {4, 1};
Transfinite Line{1,3} = 11;
Transfinite Line{2,4} = 21;
Line Loop(1) = { 1,2,3,4 };
// surface definition ------------
Ruled Surface(1) = {1};
Transfinite Surface(1) = {1,2,3,4};
Recombine Surface{1};
// at this point there is a surface meshed
// with quadrangle elements:
// resolution is given by 10 X 20 elements
// ----------------------------------------
// 3d volume creation from the extrusion of
// the meshed surface
// ----------------------------------------
volFluid[] = Extrude {0,0.15,0} { Surface{1};   Layers{6}; Recombine; };
// fluid volume
Physical Volume(1) = { volFluid[1] };
// Ruled Surface(2) = { volFluid[0] };
// // make a 2nd extrusion to define the solid domain
// vol[] = Extrude { 0,0.005,0 }{ volFluid[0]; Layers{3}; Recombine; };
// // structural volume
// Physical Volume(2) = { vol[1] };
// // interface surface
// Physical Surface(3)= { volFluid[0] };

