uses Series;
 
procedure TForm1.FormCreate(Sender: TObject);
var i: Integer;
begin
  for i:=0 to 2 do
    with Chart1.AddSeries(TBarSeries) as TBarSeries do
    begin
      FillSampleValues;
      Marks.Visible:=False;
      MultiBar:=mbStacked;
 
      if i<2 then
         StackGroup:=0
      else
        StackGroup:=1;
 
      Chart1[i].YValue[i+1]:=-Chart1[i].YValue[i+1];
    end;
end;

procedure TFormTestTeeChart.FormCreate (Sender : TObject);
const Vals : array [0 .. 5] of Integer = (+10, +20, +30, -30, -20, -10);
var i, j: Integer;
begin
  for i:=0 to 2 do
    with Chart1.AddSeries (TBarSeries) as TBarSeries do
    begin
      FillSampleValues;
      Marks.Visible:=False;
      MultiBar:=mbStacked;
 
      if i < 1 then // if i < 2 then
         StackGroup:=0
      else
        StackGroup:=1;
 
      // Chart1[i].YValue[i+1]:=-Chart1[i].YValue[i+1];
      for j := Low (Vals) to High (Vals) do
        case i of
          0 : Chart1[i].YValue[j] := Vals[j] * 1.5;
          1 : Chart1[i].YValue[j] := Vals[j] * 0.5;
          2 : Chart1[i].YValue[j] := Vals[j];
        end;
    end;
end; {TFormTestTeeChart.FormCreate}