function flatchart() {
  const srcSheetName = "data"; // This is the source sheet name.
  const dstSheetName = "flat"; // Please set the destination sheet name.
  let out = [];
  Object.prototype.get1stNonEmptyRowFromBottom = function (columnNumber, offsetRow = 1) {
    const search = this.getRange(offsetRow, columnNumber, this.getMaxRows()).createTextFinder(".").useRegularExpression(true).findPrevious();
    return search ? search.getRow() : offsetRow;
  };
  const ss = SpreadsheetApp.getActiveSpreadsheet();
  const srcSheet = ss.getSheetByName(srcSheetName);
  const lastRow = srcSheet.get1stNonEmptyRowFromBottom(1);
  const [[, , , ...header1], ...srcValues] = srcSheet.getRange("A1:AG" + lastRow).getValues();
  for (var i = 1; i < srcValues.length; i++) {
    for (var c = 3; c < srcValues[0].length - 1; c++) {
      let x = [];
      x.push(srcValues[i][0])
      x.push(srcValues[i][1])
      x.push(srcValues[i][2])
      x.push(header1[c - 3])
      x.push(srcValues[i][c])
      x.push(srcValues[i][c + 1])
      c++;
      out.push(x)
    }
  }
  const dstSheet = ss.getSheetByName(dstSheetName);
  dstSheet.getRange(dstSheet.getLastRow() + 1, 1, out.length, out[0].length).setValues(out);
}