void tm() 
{
   TMarker *mo[100];
   for (Int_t i= 0; i < 100; i++) mo[i] = NULL;
   TCanvas * c1 = new TCanvas("c1", "Markers", 100,100, 500, 500);
   c1->Range(0, 0, 100, 100);
   TMarker *m;
   Double_t x, y;
   Double_t d2r = TMath::Pi() / 180;
   Double_t radius = 10;
   Style_t mstyle = 20;
   Int_t ip = 0;
   for (Int_t i= 0; i < 10; i++) {
      ip = 0;
      mstyle = 20;
      radius = 5 + 2 * i;
      for (Double_t ang = 0; ang < 360; ang += 30) {
         x = 50 + radius * TMath::Cos(d2r * ang);
         y = 50 + radius * TMath::Sin(d2r * ang);
         if (mo[ip] != NULL) delete mo[ip];
         mo[ip] = new TMarker(x, y, mstyle);
         mstyle++;
         mo[ip]->Draw();
         ip++;
         radius = radius + ip;
         c1->Modified();
         c1->Update();
         gSystem->Sleep(100);
      }
   }
}