function createSpreadsheetData() {
  var rows = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 100;
  var columns = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : 4;
  var _rows = [];
  var i;
  var j;

  for (i = 0; i < rows; i++) {
    var row = [];

    for (j = 0; j < columns; j++) {
      row.push(spreadsheetColumnLabel(j) + (i + 1));
    }

    _rows.push(row);
  }

  return _rows;
}
Creates 2D array of Excel-like values "A1", "A2", ...

@param {Number} rows Number of rows to generate.
@param {Number} columns Number of columns to generate.
@returns {Array}