Пересекаются ли фигуры?

[Stilet]

Если еще актуально вот набросок:

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X,
      Y: Integer);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
  Y: Integer);
  var cx,cy,rad:integer;
begin
cx:=400;cy:=400;rad:=100;
Canvas.FillRect(Form1.ClientRect);
Canvas.Ellipse(cx-rad div 2,cy-rad div 2,cx+rad div 2,cy+rad div 2);
Canvas.Rectangle(x,y,x+100,y+100);
if
 ((abs(x-cx)<(rad div 2))or (abs(x+100-cx)<(rad div 2)))
and
 ((abs(y-cy)<(rad div 2))or (abs(y+100-cy)<(rad div 2)))
then caption:='da'
else caption:='net';
end;

end.