public String row(int i)
    throws Exception
  {

    int h = this.height();
    // Sanity check
    if ((i < 0) || (i >= h))
      {
        throw new Exception("Invalid row " + i);
      } // if the row is invalid

    String result;
    result = "";
    //loop to make one line
    for (int k = 0; k < this.width; k++)
      {
        result = result.concat(this.builder);
      }

    return result;
  } // row(int)