{ PascalABC.Net}
uses GraphABC;

procedure Draw(x, y, x1, y1, k: integer);
begin
  if k > 0 then 
  begin
    var xn := (x + x1) div 2 + (y1 - y) div 2;
    var yn := (y + y1) div 2 - (x1 - x) div 2;
    
    Dec(k);
    Draw(x, y, xn, yn, k); 
    Draw(x1, y1, xn, yn, k); 
  end 
  else
    Line(x, y, x1, y1);
end;

begin
  LockDrawing();
  Draw(200, 300, 500, 300, 20);
  Redraw();
end.