uses GraphABC; 
const
  Rotate = 50;
  MaxAng = 10;

var
  Ang: integer;

procedure Draw(x, y, l, angle: real; s: integer);
begin
  var ang1 := DegToRad(angle);
  var cx := x + l * Cos(ang1); 
  var cy := y + l * Sin(ang1);
  
  SetPenWidth(s); 
  Line(Round(x), Round(y), Round(cx), Round(cy));
  
  if l > 1 then 
  begin
    var l2 := l * 0.72; 
    l := l * 0.5;
    
    if s > 1 then Dec(s);
    var ang3 := angle + Ang;
    Draw(cx, cy, l2, ang3, s); 
    Draw(cx, cy, l, ang3 + Rotate, s); 
    Draw(cx, cy, l, ang3 - Rotate, s); 
  end; 
end;


begin
  var W := Window.Width / 2;
  var H := Window.Height;
  
  SetPenColor(clDarkGreen); 
  SetSmoothingOff(); 
  
  LockDrawing();
  while true do
  begin
    for Ang := -MaxAng to MaxAng do
    begin
      ClearWindow();
      Draw(W, H, 100, -90, 2);
      Redraw();
    end;
    for Ang := MaxAng downto -MaxAng do
    begin
      ClearWindow();
      Draw(W, H, 100, -90, 2);
      Redraw();
    end;
  end;
end.