{
gSystem->Load("libGeom");
new TGeoManager("test","testgeometry");
TGeoMaterial *vacuum = new TGeoMaterial("vacuum");
TGeoMaterial *mat1 = new TGeoMaterial("mat1");
TGeoMaterial *mat2= new TGeoMaterial("mat2");
TGeoMedium *vac= new TGeoMedium("vac",1,vacuum);
TGeoMedium *m1= new TGeoMedium("m1",1,mat1);
TGeoMedium *m2= new TGeoMedium("m2",1,mat2);
TGeoVolume *world = gGeoManager->MakeBox("world",vac,1000,1000,1000);
TGeoVolume *vol1 = gGeoManager->MakeBox("vol1",m1,100,200,300);
TGeoVolume *vol2 = gGeoManager->MakeBox("vol2",m2,300,200,100);
gGeoManager->SetTopVolume(world);
world->AddNode(vol1,1);
world->AddNode(vol2,2);
gGeoManager->CloseGeometry();
world->Draw("ogl");
TGeoPhysicalNode *p1 = gGeoManager->MakePhysicalNode("/world_1/vol1_1");
TGeoPhysicalNode *p2 = gGeoManager->MakePhysicalNode("/world_1/vol2_2");
TGeoTranslation *move  = new TGeoTranslation(100,200,300);
TGLViewer* viewer= (TGLViewer*)(gPad->GetViewer3D());
//here you can see the toy bricks
////let the viewer live on it's own, and modify what you see from the prompt
//example manipulations follow
vol1->SetLineColor(kRed);
viewer->UpdateScene();
p1->Align(move);
viewer->UpdateScene();
}