uses GraphABC; 
const
  H = 30;

procedure Draw(x, y, x1, y1: integer; connect: boolean);
begin
  var d := x1 - x;
  
  if d > 10 then 
  begin
    if connect then Line(x, y, x1, y1);
    
    var xp1 := Round(x + d / 3);
    var xp2 := Round(x + d * 2 / 3);
    
    var y2 := y + H;
    var y3 := y2 - 1;
    DrawRectangle(x, y, xp1, y2); 
    DrawRectangle(xp2, y, x1, y2); 
    Draw(x, y + H - 1, xp1, y3, false); 
    Draw(xp2, y3, x1, y3, false); 
  end; 
end;

begin
  LockDrawing();
  Draw(100, 100, 600, 100, true);
  Redraw();
end.