Как создать движение объекта?

unit Unit1;
 
{$mode objfpc}{$H+}
 
interface
 
uses
  Classes, SysUtils, Forms, Controls, Graphics, Dialogs, ExtCtrls, crt, LCLType;
 
type
 
  { TForm1 }
 
  TForm1 = class(TForm)
    Image1: TImage;
    Timer1: TTimer;
    procedure FormCreate(Sender: TObject);
    procedure FormKeyDown(Sender: TObject; var Key: word; Shift: TShiftState);
    procedure FormKeyUp(Sender: TObject; var Key: word; Shift: TShiftState);
    procedure Timer1Timer(Sender: TObject);
  private
 
  public
 
  end;
 
type
 
  { TT }
 
  TT = class(TObject)
    x, y, num: int64;
    procedure draw(img: TImage);
  end;
 
type
 
  { TU }
 
  TU = class(TObject)
    x, y, xx, yy: int64;
    procedure draw(img: TImage);
  end;
 
var
  Form1: TForm1;
  t1, t2, ust: TPortableNetworkGraphic;
  w, s, a, d: boolean;
  list: TList;
  t: TT;
  us: TU;
 
implementation
 
{$R *.lfm}
 
{ TU }
 
procedure TU.draw(img: TImage);
begin
  xx := x;
  yy := y;
  img.Canvas.retri(xx, yy, );
  img.Canvas.Draw(x, y, ust);
end;
 
{ TT }
 
procedure TT.draw(img: TImage);
var
  i: int64;
begin
 
  num := random(2);
  x := random(form1.Width);
  y := Random(form1.Height);
  case num of
    0: img.Canvas.Draw(x, y, t1);
    1: img.Canvas.Draw(x, y, t2);
 
  end;
end;
 
{ TForm1 }
 
procedure TForm1.FormCreate(Sender: TObject);
begin
  randomize;
  us := TU.Create;
  t := TT.Create;
 
  list := TList.Create;
  t1 := TPortableNetworkGraphic.Create;
  t2 := TPortableNetworkGraphic.Create;
  ust := TPortableNetworkGraphic.Create;
  t1.LoadFromFile('christmas.png');
  t2.LoadFromFile('tools-and-utensils.png');
  ust.LoadFromFile('profile (1).png');
  Image1.Canvas.Brush.Color := clWhite;
  image1.Canvas.Rectangle(0, 0, 800, 600);
end;
 
procedure TForm1.FormKeyDown(Sender: TObject; var Key: word; Shift: TShiftState);
begin
  if key = vk_up then
    w := True;
  if key = vk_down then
    s := True;
  if key = vk_left then
    a := True;
  if key = VK_RIGHT then
    d := True;
end;
 
procedure TForm1.FormKeyUp(Sender: TObject; var Key: word; Shift: TShiftState);
begin
  if key = vk_up then
    w := False;
  if key = vk_down then
    s := False;
  if key = vk_left then
    a := False;
  if key = VK_RIGHT then
    d := False;
end;
 
procedure TForm1.Timer1Timer(Sender: TObject);
begin
  //  Image1.Canvas.Pen.Style:=psClear;
  if w = True then
    us.y := us.y - 1;
  if s = True then
    us.y := us.y + 1;
  if a = True then
    us.x := us.x - 1;
  if d = True then
    us.x := us.x + 1;
  us.draw(Image1);
  //  t.draw(Image1);
end;
 
end.