void shade2() {
   TCanvas *c1 = new TCanvas("c1","A Simple Graph Example",200,10,700,500);

   c1->SetGrid();
   c1->DrawFrame(0,0,2.2,12);
   
   const Int_t n = 20;
   Double_t x[n], y[n],ymin[n], ymax[n];
   Int_t i;
   for (i=0;i<n;i++) {
     x[i] = 0.1+i*0.1;
     ymax[i] = 10*sin(x[i]+0.2);
     ymin[i] = 8*sin(x[i]+0.1);
   }
   TGraph *grmin = new TGraph(n,x,ymin);
   TGraph *grmax = new TGraph(n,x,ymax);
   TGraph *grshade = new TGraph(2*n);
   for (i=0;i<n;i++) {
      grshade->SetPoint(i,x[i],ymax[i]);
      grshade->SetPoint(n+i,x[n-i-1],ymin[n-i-1]);
   }
   grshade->SetFillStyle(3013);
   grshade->SetFillColor(16);
   grshade->Draw("f");
   grmin->SetLineWidth(4);
   grmin->SetMarkerColor(4);
   grmin->SetMarkerStyle(21);
   grmax->SetLineWidth(4);
   grmax->SetMarkerColor(4);
   grmax->SetMarkerStyle(21);
   grmin->Draw("cp");
   grmax->Draw("cp");
}