void gggg()
{
   //
   // gggg vertex
   //
   TCanvas *c1 = new TCanvas("gggg", "gggg", 740,40, 300, 300);
   c1->Range(3, 3, 57, 57);
   Int_t linsav = gStyle->GetLineWidth();
   gStyle->SetLineWidth(3);
   TLatex t;
   t.SetTextAlign(22);
   t.SetTextSize(0.1);
   TLine * l;

   // 4 gluons
   lc = new TCurlyLine(50, 50, 30, 30);  lc->SetCurly(); lc->Draw();
   lc = new TCurlyLine(10, 50, 30, 30);  lc->SetCurly(); lc->Draw();
   lc = new TCurlyLine(50, 10, 30, 30);  lc->SetCurly(); lc->Draw();
   lc = new TCurlyLine(10, 10, 30, 30);  lc->SetCurly(); lc->Draw();

   t.DrawLatex(7,53,"g");
   t.DrawLatex(53,53,"g");
   t.DrawLatex(7,7,"g");
   t.DrawLatex(53,7,"g");

   c1->Update();
   gStyle->SetLineWidth(linsav);
}