Как работать с массивом компонентов

unit Unit1; 

interface 

uses 
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, 
  Dialogs, StdCtrls, ExtCtrls, Grids; 

type 
  TForm1 = class(TForm) 
    procedure FormCreate(Sender: TObject); 
  private 
    { Private declarations } 
  public 
  Procedure PanelOnClick(Sender: TObject); 
    { Public declarations } 

  end; 

var 
       Form1: TForm1; 
       Panel: array[0..811] of Tpanel; 
       x,y,z:integer; 
implementation 

{$R *.dfm} 

procedure TForm1.FormCreate(Sender: TObject); 
var i,j:integer; 
begin 
y:=-20; 
Width:=585; 
Height:=586; 
for j:=0 to 32 do 
 begin 
  y:=y+20; 
  i:=0; 
  x:=0; 
for i:=0 to 28 do 
 begin 
  Panel:=Tpanel.Create(Self); 
  Panel.Parent:=self; 
  Panel.Width:=20; 
  Panel.Height:=20; 
  Panel.Tag:=z; 
  Panel.Left:=x; 
  Panel.Top:=y; 
  Panel.OnClick:=PanelOnClick; 
  x:=x+20; 
  Inc(z); 
  end; 
 end; 
end; 

Procedure TForm1.PanelOnClick(Sender: TObject); 
var a:integer; 
begin 
a:=(Sender as TPanel).tag; 
ShowMessage(FloatToStr(a)); 
Panel[a].Color:=clBlack; 
end; 
end.

Procedure TForm1.PanelOnClick(Sender: TObject);
var a:integer;
begin
(Sender as TPanel).Color:=clBlack;
end;