Draw Gradient Aminate Lines

procedure TForm1.Button1Click(Sender: TObject);
  Procedure SpiralDraw(Count:Integer);
  var
    cs, co, sn, si, cx, cy, x, y, ad, sf, xo: real;
    Counter:Integer;
    j, i: byte;
    xp, yp, color: Integer;
  begin
    cs := Cos(pi / 3);
    co := Cos(pi / 36);
    sn := Sin(pi / 3);
    si := Sin(pi / 36);
    cx := Round(Form1.Width/2);
    cy := Round(Form1.Height/2);
    ad := 1.16;
    sf := 1.06;
    Color:=20200;
    Counter:=0;
    xp := trunc(cx + 12 * ad);
    yp := trunc(cy + 0);
    Form1.Canvas.MoveTo(Xp,Yp);
    repeat
      Inc(Counter);
      x := 12;
      y := 0;
      For j := 0 to 70 do begin
        For i := 0 to 6 do begin
          Form1.Canvas.Pen.Color:=Color;
          Color:=Color+1;
          xp := trunc(cx + x * ad);
          yp := trunc(cy + y);
          If (i = 0) Then Form1.Canvas.MoveTo(xp, yp);
          Form1.Canvas.LineTo(xp, yp);
          xo := x * cs - y * sn;
          y := x * sn + y * cs;
          x := xo;
        End;
        xo := sf * (x * co - y * si);
        y := sf * (x * si + y * co);
        x := xo;
      End;
    until Counter>Count;
  End;
begin
  SpiralDraw(500);
end;