...
var
  Form1: TForm1;
  nummern: Array[1..8,1..8] of TSpeedButton;
  drei : integer;
  gedrueckt: Array[1..3] of TPoint;

implementation

{$R *.dfm}

procedure TForm1.FormShow(Sender: TObject);
var i,j,x,y: integer;
begin
 drei := 1;

 x := 20;
 y := 20;
 for i := 1 to 8 do
  begin
   for j := 1 to 8 do
      begin
         Nummern[i,j] := TSpeedButton.Create(Self);
         Nummern[i,j].Parent := GroupBox1;
         Nummern[i,j].Show;
         Nummern[i,j].Left := y;
         Nummern[i,j].Top := x;
         Nummern[i,j].Height := 50;
         Nummern[i,j].Width := 50;
         Nummern[i,j].OnClick := ZahlClick;
         Nummern[i,j].Tag := i*10+j;
         inc(x,50);
       end;
     x := 20;
     inc(y,50);
  end;
end;

procedure TForm1.ZahlClick(Sender: TObject);
var x,y, i, j: integer;
begin
  If Sender is TSpeedButton then
  begin
    If drei in [1,2,3] then
    begin
      x := StrToInt(Copy(IntToStr(TSpeedButton(Sender).Tag),1,1));
      y := TSpeedButton(Sender).Tag Mod 10;
      If not Nummern[x,y].Down then
      begin
        Nummern[x,y].GroupIndex := drei;
        Nummern[x,y].Down := true;
        gedrueckt[drei].X := x;
        gedrueckt[drei].Y := y;
        inc(drei);
      end;
      If drei = 4 then
      begin
        for i := 1 to 3 do
        begin
          Nummern[gedrueckt[i].X,gedrueckt[i].Y].Down := false;
          Gedrueckt[i].X := 0;
          Gedrueckt[i].Y := 0;
        end;
        drei := 1;
      end;

    end;
  end;
end;