// ROOT macro

void makeFakeTree() {
  TFile* tf = new TFile("fakeTree.root", "RECREATE");
  TTree* tt = new TTree("tt", "Gay Tree");
  float x[12];
  int len;

  tt->Branch("len", &len, "len/I");
  tt->Branch("x", x, "x[len]/F");

  for (int i=0; i < 15; i++) {
    len = rand() % 10;
    if (len == 0)
      continue;

    for (int j=0; j < len; j++)
      x[j] = j;
    tt->Fill();

  }

	tf->Write();
}