(ignored inputs)COMMENT Exercise 4.2.2 of \cite{Ohl02}
Rewrite Rules:
   [ b(w(?x)) -> w(w(w(b(?x)))),
     w(b(?x)) -> b(?x),
     b(b(?x)) -> w(w(w(w(?x)))),
     w(w(?x)) -> w(?x) ]
Apply Direct Methods...
Inner CPs:
   [ b(b(?x_1)) = w(w(w(b(b(?x_1))))),
     b(w(?x_3)) = w(w(w(b(w(?x_3))))),
     w(w(w(w(b(?x))))) = b(w(?x)),
     w(w(w(w(w(?x_2))))) = b(b(?x_2)),
     b(w(w(w(b(?x))))) = w(w(w(w(w(?x))))),
     w(b(?x_1)) = w(b(?x_1)),
     b(w(w(w(w(?x))))) = w(w(w(w(b(?x))))),
     w(w(?x)) = w(w(?x)) ]
Outer CPs:
   [  ]
not Overlay, check Termination...
Terminating, WCR
Knuth&Bendix
Direct Methods: CR

Final result: CR
/local-scratch/hzankl/2012/cops2012/68.trs: Success(CR)
(6 msec.)