type
    TForm1 = class(TForm)
        Button1: TButton;
        Button2: TButton;
        procedure Button1Click(Sender: TObject);
        procedure Button2Click(Sender: TObject);
        procedure FormCreate(Sender: TObject);
    private
        const n = 20;
        p: array of point;
    public
    end;

var Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var
    cx, cy, i: integer;
    a: real;
begin
    setlength(p, n);
    a := 0;
    cx := Form1.GetWidth div 2;
    cy := Form1.GetHeight div 2;

    for i := 0 to n - 1 do
    begin
        p[i].x := cx + round(240 * cos(a));
        p[i].y := cy + round(240 * sin(a));
        a := a + 2 * Pi / n;
    end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
    i, j: integer;
begin
    With Form1.Canvas do
    begin
        Poligon(p);
        for i := 0 to n - 1 do
            for j := 0 to n - 1 do
                if i <> j then
                begin
                    MoveTo(p[i].x, p[i].y);
                    LineTo(p[j].x, p[j].y);
                end;
    end;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
    Form1.Close;
end;