MAYBE
Input TRS:
      1: a(d(x1)) -> d(b(c(b(d(x1)))))
      2: a(x1) -> b(b(f(b(b(x1)))))
      3: b(d(b(x1))) -> a(d(x1))
      4: d(f(x1)) -> b(d(x1))
Number of strict rules: 4
Direct POLO(bPol) ... failed.
Uncurrying ... failed.
Dependency Pairs:
     #1: #a(x1) -> #b(b(f(b(b(x1)))))
     #2: #a(x1) -> #b(f(b(b(x1))))
     #3: #a(x1) -> #b(b(x1))
     #4: #a(x1) -> #b(x1)
     #5: #b(d(b(x1))) -> #a(d(x1))
     #6: #b(d(b(x1))) -> #d(x1)
     #7: #a(d(x1)) -> #d(b(c(b(d(x1)))))
     #8: #a(d(x1)) -> #b(c(b(d(x1))))
     #9: #a(d(x1)) -> #b(d(x1))
     #10: #d(f(x1)) -> #b(d(x1))
     #11: #d(f(x1)) -> #d(x1)
Number of SCCs: 1, DPs: 7
  SCC { #3..6 #9..11 }
POLO(Sum)... POLO(max)... QLPOS... POLO(mSum)... QWPOpS(mSum)... Mat2b... failed.
Finding a loop...  failed.