void test1()
{
  // Mirror parameters
  const Double_t kR1 = 1363;
  const Double_t kRad = 425;
  const Double_t kR2 = 1363 + 8;

  TGeoManager* manager = new TGeoManager("manager", "test");

  // Make the world
  TGeoBBox* box1 = new TGeoBBox("box1", 2000, 2000, 2000);
  TGeoVolume *top = new TGeoVolume("top", box1);
  manager->SetTopVolume(top);

  // Mirror
  Double_t r = kR2*TMath::Tan(TMath::ASin(kRad/kR1));
  Double_t deg2rad = TMath::Pi()/180;

  TGeoPgon* cut = new TGeoPgon("cut", 0, 360, 6, 2);
  cut->DefineSection(0, 0, 0, 0);
  cut->DefineSection(1, kR2, 0, r*TMath::Sqrt(3)/2);
      
  TGeoSphere* mirSph = new TGeoSphere("mirSph", kR1, kR2, 0,
				      TMath::ASin(kRad/kR1)/deg2rad);
  TGeoCompositeShape* mirSphCut = new TGeoCompositeShape("cs", "mirSph*cut");
  TGeoVolume* mirror = new TGeoVolume("mirror", mirSphCut);
  top->AddNode(mirror, 1);

  manager->CloseGeometry();

  top->Draw();
}