unit Unit1;

{$mode objfpc}{$H+}

interface

uses

  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, ExtCtrls;

type

  { TForm1 }

  TForm1 = class(TForm)

    Shape1: TShape;

    Timer1: TTimer;

    Timer2: TTimer;

    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);

    procedure Timer1Timer(Sender: TObject);

    procedure Timer2Timer(Sender: TObject);

  private

    { private declarations }

  public

    { public declarations }

  end;

const

  G = 1000000;

var

  Form1: TForm1;

  mx: double = 0;

  my: double = 0;

  x: double = 200;

  y: double = 200;

  vx: double = 0;

  vy: double = 0;

implementation

{$R *.lfm}

procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,

  Y: Integer);

begin

  mx := x;

  my := y;

end;

procedure TForm1.Timer1Timer(Sender: TObject);

var

  dx, dy, d: double;

  ax, ay: double;

  t, r: double;

begin

  dx := mx - x;

  dy := my - y;

  d := sqrt(dx*dx + dy*dy);

  t := Timer1.Interval/1000;

  r := Shape1.Width/2;

  ax := G*dx/(d*d*d);

  ay := G*dy/(d*d*d);

  if d < 10 then begin ax:=0; ay:=0; end;

  vx := vx + ax*t;

  vy := vy + ay*t;

  x := x + vx*t;

  y := y + vy*t;

  if x < r then begin x:=r; vx:=abs(vx); end;

  if x > ClientWidth-r then begin x:=ClientWidth-r; vx:=-abs(vx); end;

  if y < r then begin y:=r; vy:=abs(vy); end;

  if y > ClientHeight-r then begin y:=ClientHeight-r; vy:=-abs(vy); end;

end;

procedure TForm1.Timer2Timer(Sender: TObject);

begin

  Shape1.Left := round(x - Shape1.Width/2);

  Shape1.Top  := round(y - Shape1.Height/2);

end;

end.