Point(1) = {0,0,0,0};
Point(2) = {10,0,0,0};
Point(3) = {10,10,0,0};
Point(4) = {7,10,0,0};
Point(5) = {2,2,0,0};
Point(6) = {0,2,0,0};
Line(1) = {1,2};
Line(2) = {2,3};
Line(3) = {3,4};
Line(4) = {4,5};
Line(5) = {5,6};
Line(6) = {1,6};
Point(7) = {6.5,5.5,0,0.1};
Point(8) = {8.7,5.8,0,0.1};
Point(9) = {8.9,1.9,0,0.1};
Point(10) = {5.5,1.7,0,0.1};
Line(7) = {7,8};
Line(8) = {8,9};
Line(9) = {10,9};
Line(10) = {7,10};
Extrude {{0,1,0}, {0,0,0}, Pi/10} {
  Line{10,9,8,7,6,5,4,3,2,1};
}
Line Loop(46) = {2,3,4,5,-6,1};
Line Loop(47) = {10,9,-8,-7};
Plane Surface(48) = {46,47};
Line Loop(49) = {31,28,-6,43,39,35};
Line Loop(50) = {23,19,-15,-11};
Plane Surface(51) = {49,50};
Surface Loop(52) = {38,48,42,51,34,30,45,14,18,22,26};
Volume(53) = {52};
Characteristic Length
{45,32,26,2,18,3,16,4,5,1,6,7,10,9,8,39,12,11,40,27,20,47,46} = 0.5;
Mesh.Algorithm3D=1;
