{
   
   THStack *hs = new THStack("hs","Stacked 1D histograms");

   //create three 1-d histograms
   TH1F *h1st = new TH1F("h1st","test hstack",100,-4,4);
   h1st->FillRandom("gaus",20000);
   h1st->SetFillColor(kRed);
   h1st->SetFillStyle(3002);
   hs->Add(h1st);
   TH1F *h2st = new TH1F("h2st","test hstack",100,-4,4);
   h2st->FillRandom("gaus",15000);
   h2st->SetFillColor(kBlue);
   h2st->SetFillStyle(3003);
   hs->Add(h2st);
   TH1F *h3st = new TH1F("h3st","test hstack",100,-4,4);
   h3st->FillRandom("gaus",10000);
   h3st->SetFillColor(kGreen);
   h3st->SetFillStyle(3004);
   hs->Add(h3st,"E");
   
   TCanvas *cst = new TCanvas("cst","stacked hists",10,10,700,700);
   hs->Draw();
}