{
	/// Creating histograms

	Int_t nbins=7 ; 

	TH2D* histo1 = new TH2D ("histo1","histo1",nbins,0.,nbins*1.,nbins,0.,nbins*1.) ; histo1->SetStats(kFALSE) ; histo1->SetFillColor(kRed) ; histo1->SetMarkerColor(kRed) ; histo1->SetMarkerStyle(20) ;
		histo1->SetBinContent((nbins/2+1)  ,(nbins/2+1)  ,5.) ; 
		histo1->SetBinContent((nbins/2+1)-1,(nbins/2+1)  ,3.) ;   
		histo1->SetBinContent((nbins/2+1)+1,(nbins/2+1)  ,4.) ;
		histo1->SetBinContent((nbins/2+1)  ,(nbins/2+1)-1,2.) ;
		histo1->SetBinContent((nbins/2+1)  ,(nbins/2+1)+1,1.) ;

	Int_t shiftxy=1 ; Double_t shiftz=0. ;
	TH2D* histo2 = new TH2D ("histo2","histo2",nbins,0.,nbins*1.,nbins,0.,nbins*1.) ; histo2->SetStats(kFALSE) ; histo2->SetFillColor(kBlue) ; histo2->SetMarkerColor(kBlue) ; histo2->SetMarkerStyle(20) ;
	for (Int_t col=histo2->GetNbinsX(); col>=shiftxy; col--) { 
		for (Int_t row=histo2->GetNbinsY(); row>=shiftxy; row--) { 
			histo2->SetBinContent( col,row, histo1->GetBinContent(col-shiftxy,row-shiftxy)+shiftz ) ;
		}
	}

	/// Creating a global THStack

	TH2D* histo_dummy = (TH2D*) histo1->Clone("histo_dummy") ; histo_dummy->Reset() ; histo_dummy->SetFillColor(kWhite) ;  /// Empty histogram to get a white floor (equivalent to http://root.cern.ch/phpBB3//viewtopic.php?t=4598)
	THStack *hstack12 = new THStack ("hstack12","hstack12") ;
		hstack12->Add(histo_dummy) ;
		hstack12->Add(histo1) ;
		hstack12->Add(histo2) ;

	/// Creating a global "nostack THStack" keeping only the highest valued bin  (see http://root.cern.ch/phpBB3/viewtopic.php?f=3&t=6159)

	Double_t y1=-1., y2=-1. ;
	TH2D* histo1__ = (TH2D*) histo1->Clone("histo1__") ; 
	TH2D* histo2__ = (TH2D*) histo2->Clone("histo2__") ; 
	if ( ( histo1__->GetNbinsX() == histo2__->GetNbinsX() ) || ( histo1__->GetNbinsY() == histo2__->GetNbinsY() ) ) {
		for (Int_t col=1; col<=histo1__->GetNbinsX(); col++) { 
			for (Int_t row=1; row<=histo1__->GetNbinsY(); row++) { 
				y1 = histo1->GetBinContent(col,row) ; y2 = histo2->GetBinContent(col,row) ;
				if ( y2 >= y1 ) { histo1__->SetBinContent(col,row,0.) ; } else { histo2__->SetBinContent(col,row,0.) ; }
			}
		}
	}
	THStack *hstack12__ = new THStack ("hstack12__","hstack12__") ;
		hstack12__->Add(histo_dummy) ;
		hstack12__->Add(histo1__) ;
		hstack12__->Add(histo2__) ;

	/// Plotting everything

	TCanvas *canvas_ = new TCanvas ("canvas_","canvas_",0,0,gClient->GetDisplayWidth(),gClient->GetDisplayHeight()) ; 
		canvas_->Divide(2,1) ;
		canvas_->cd(1) ; hstack12  ->SetTitle("THStack::Draw(\"lego1\")") ; hstack12  ->DrawClone("lego1,fb") ;
		canvas_->cd(2) ; hstack12__->SetTitle("THStack::Draw(\"lego1\")") ; hstack12__->DrawClone("lego1,fb") ;
	gPad->Update() ;
	canvas_->SaveAs("THStack_lego_nostack_.gif") ;
	canvas_->SaveAs("THStack_lego_nostack_.png") ;
}