{
  TNtuple *n = new TNtuple("n", "n", "a:b:c");
  n->SetMarkerStyle(20);
  n->SetMarkerSize(1);
  
  for (Int_t i = 0; i < 20; i++) n->Fill(gRandom->Rndm(), gRandom->Rndm(), i);
  
  TCanvas *c = new TCanvas("c", "c");
  c->Divide (2, 1);
  
  TH2F *h;
  
  c -> cd(1);
  cout << endl;
  TH2F *hold = new TH2F("hold", "hold", 100, 0, 1, 100, 0, 1);
  // hold->SetMarkerStyle(20);
  // hold->SetMarkerSize(1);
  cout << "TH2F hold histogram exists in advance -> " << hold << endl;
  n->Draw("a:b>>hold", "", "");
  h = (TH2F *)(gPad->GetPrimitive("hold"));
  cout << "gPad -> " << h << " -> "; if (h) h->Print(); else cout << "hold" << endl;
  h = (TH2F *)(gROOT->FindObject("hold"));
  cout << "gROOT -> " << h << " -> "; if (h) h->Print(); else cout << "hold" << endl;
  
  c -> cd(2);
  cout << endl;
  cout << "TH2F hnew histogram DOES NOT exist in advance" << endl;
  n->Draw("a:b>>hnew", "", "");
  h = (TH2F *)(gPad->GetPrimitive("hnew"));
  cout << "gPad -> " << h << " -> "; if (h) h->Print(); else cout << "hnew" << endl;
  h = (TH2F *)(gROOT->FindObject("hnew"));
  cout << "gROOT -> " << h << " -> "; if (h) h->Print(); else cout << "hnew" << endl;
  if (gROOT->GetVersionInt() > 59999) { // ROOT 6
    h = (TH2F *)(gPad->GetPrimitive("hnew_copy"));
    cout << "gPad -> " << h << " -> "; if (h) h->Print(); else cout << "hnew_copy" << endl;
    h = (TH2F *)(gROOT->FindObject("hnew_copy"));
    cout << "gROOT -> " << h << " -> "; if (h) h->Print(); else cout << "hnew_copy" << endl;
  }
  
  c->cd(0);
  cout << endl;
}