void mario() {
   TCanvas *c1 = new TCanvas("c1","test",600,800);
   c1->Divide(1,2);
   TH1F *h1 = new TH1F("h1","test1",100,-3,3);
   TH2F *h2 = new TH2F("h2","test2",30,-3,3,30,-3,3);
   Double_t ymax = 3000;
   TArrow *arrow = new TArrow(0,ymax,0.5,0,0.02,"|>");
   h1->SetMaximum(ymax);
   TPad *pad1 = (TPad*)c1->cd(1);
   h1->Draw();
   arrow->Draw();
   TPad *pad2 = (TPad*)c1->cd(2);
   h2->Draw();
   TBox *box = new TBox(-0.1,0.1,0.1,0.1);
   box->SetFillStyle(3004);
   box->SetFillColor(kRed);
   box->Draw();
   TRandom3 r;
   for (Int_t i=0;i<100000;i++) {
      h1->Fill(r.Gaus(0,1));
      h2->Fill(r.Gaus(0,1),r.Gaus(0.2,0.8));
      if (i %200 == 0) {
         Int_t imax = h1->GetMaximumBin();
         arrow->SetX2(h1->GetXaxis()->GetBinCenter(imax));
         arrow->SetY2(h1->GetBinContent(imax));
         pad1->Modified();
         Double_t xmean = h2->GetMean(1);
         Double_t xrms  = h2->GetRMS(1);
         Double_t ymean = h2->GetMean(2);
         Double_t yrms  = h2->GetRMS(2);
         box->SetX1(xmean-xrms);
         box->SetY1(ymean-yrms);
         box->SetX2(xmean+xrms);
         box->SetY2(ymean+yrms);
         pad2->Modified();
         c1->Update();
      }
   }
}