A (A) [Y/n/?] (NEW) 
  A0 (A0) [Y/n/?] (NEW) 
    A1_0 (A0_0) [N/y/?] (NEW) 
  A1 (A1) [Y/n/?] (NEW) 
    choice
    > 1. A1_0 (A1_0) (NEW)
      2. A1_1 (A1_1) (NEW)
    choice[1-2?]: 
B (B) [N/y/?] (NEW) 
C (C) [N/y/?] (NEW)