| | | +--> 1.D
  | | | ---> 3.AB
  | | | +--> 3.E
  | | | +--> 4.C
  | |   +--> 3.C
  | |   +--> 4.ACD
  | | ---> 2.c
  | | | `--> 2.d
  | | `--> 2.d
  | | |--> 2.r.
  | | |--> 3.r.
  | `--> Sile