MAYBE
* Step 1: FromIts MAYBE
    + Considered Problem:
        Rules:
          0. f6(A,B,C,D) -> f16(A,B,C,D) [1 + A >= B]                 (?,1)
          1. f6(A,B,C,D) -> f6(E,B,C,E)  [B >= 2 + A && C >= E^2]     (?,1)
          2. f6(A,B,C,D) -> f6(A,E,C,E)  [B >= 2 + A && E^2 >= 1 + C] (?,1)
          3. f0(A,B,C,D) -> f6(1,C,C,D)  True                         (1,1)
        Signature:
          {(f0,4);(f16,4);(f6,4)}
        Flow Graph:
          [0->{},1->{0,1,2},2->{0,1,2},3->{0,1,2}]
        
    + Applied Processor:
        FromIts
    + Details:
        ()
* Step 2: AddSinks MAYBE
    + Considered Problem:
        Rules:
          f6(A,B,C,D) -> f16(A,B,C,D)  [1 + A >= B]
          f6(A,B,C,D) -> f6(E,B,C,E)   [B >= 2 + A && C >= E^2]
          f6(A,B,C,D) -> f6(A,E,C,E)   [B >= 2 + A && E^2 >= 1 + C]
          f0(A,B,C,D) -> f6(1,C,C,D)   True
        Signature:
          {(f0,4);(f16,4);(f6,4)}
        Rule Graph:
          [0->{},1->{0,1,2},2->{0,1,2},3->{0,1,2}]
    + Applied Processor:
        AddSinks
    + Details:
        ()
* Step 3: Failure MAYBE
  + Considered Problem:
      Rules:
        f6(A,B,C,D)  -> f16(A,B,C,D)        [1 + A >= B]
        f6(A,B,C,D)  -> f6(E,B,C,E)         [B >= 2 + A && C >= E^2]
        f6(A,B,C,D)  -> f6(A,E,C,E)         [B >= 2 + A && E^2 >= 1 + C]
        f0(A,B,C,D)  -> f6(1,C,C,D)         True
        f16(A,B,C,D) -> exitus616(A,B,C,D)  True
      Signature:
        {(exitus616,4);(f0,4);(f16,4);(f6,4)}
      Rule Graph:
        [0->{4},1->{0,1,2},2->{0,1,2},3->{0,1,2}]
  + Applied Processor:
      Decompose Greedy
  + Details:
      We construct a looptree:
        P: [0,1,2,3,4]
        |
        `- p:[1,2] c: []
MAYBE