{
   auto c1 = new TCanvas("c1","c1",600,600);
   c1->Divide(1,2);
   auto hcol23 = new TH2F("hcol23","Option COLZ example ",40,-4,4,40,-20,20);
   auto hcol24 = new TH2F("hcol24","Option COLZ1 example ",40,-4,4,40,-20,20);
   float px, py;
   for (Int_t i = 0; i < 25000; i++) {
      gRandom->Rannor(px,py);
      hcol23->Fill(px,5*py);
      hcol24->Fill(px,5*py);
   }
   hcol23->Fill(0.,0.,-200.);
   hcol24->Fill(0.,0.,-200.);
   c1->cd(1); hcol23->Draw("COLZ");
   c1->cd(2); hcol24->Draw("COLZ1");
}