1. make_unique
  [create B4001]
  a->title = Laskar Pelangi
2. move ownership from a to b
  a is empty: true, b->id = B4001
3. hand b to a function that keeps it
  withdrawing Laskar Pelangi
  [destroy B4001]
  back in main, b is empty: true
4. a vector of owners
  [create B4002]
  [create B4003]
  observer sees Bumi Manusia
  leaving the block...
  [destroy B4002]
  [destroy B4003]
5. an owned array
  counts = 0 0 7 0
end of main
