package pack.sandbox;

/**
 * Created by User on 10.06.2017.
 */
public class Square {
  public double l;
  public double k;
  public Square(double len)
  {
    l=len;
  }
  public  double area ()
  {
    return l*l;
  }
}

package pack.sandbox;

/**
 * Created by User on 10.06.2017.
 */
public class Square {
  public double l;
  public double k;
  public double s;
  public Square(double len)
  {
    l=len;
  }
  public  double area ()
  {
    return l*l;
  }
}

add variable k