2000-01-01 transaction 1
  㐀                                          1 A @ 0.71 B
  㐀:㐁                                       -0.71 B

2000-01-02 transaction 2
  㐀:㐁:㐂                                      2 B @@ 2 C
  㐀:㐁:㐂:㐃                                   -2 C

2000-01-03 transaction 3
  㐀:㐁:㐂:㐃:㐄                                  3 C
  㐀                                         -3 C

P 2000-01-01 A  0.70 B
P 2000-01-02 A  0.71 B
P 2000-01-03 A  0.72 B