MAYBE
by ttt2 (version ttt2 1.15)
The rewrite relation of the following TRS is considered.
| Begin(a(a(a(x0)))) | → | Wait(Right1(x0)) | 
| Begin(a(a(x0))) | → | Wait(Right2(x0)) | 
| Begin(a(x0)) | → | Wait(Right3(x0)) | 
| Begin(b(b(b(x0)))) | → | Wait(Right4(x0)) | 
| Begin(b(b(x0))) | → | Wait(Right5(x0)) | 
| Begin(b(x0)) | → | Wait(Right6(x0)) | 
| Begin(c(c(c(x0)))) | → | Wait(Right7(x0)) | 
| Begin(c(c(x0))) | → | Wait(Right8(x0)) | 
| Begin(c(x0)) | → | Wait(Right9(x0)) | 
| Begin(b(x0)) | → | Wait(Right10(x0)) | 
| Begin(c(d(d(d(d(x0)))))) | → | Wait(Right11(x0)) | 
| Begin(d(d(d(d(x0))))) | → | Wait(Right12(x0)) | 
| Begin(d(d(d(x0)))) | → | Wait(Right13(x0)) | 
| Begin(d(d(x0))) | → | Wait(Right14(x0)) | 
| Begin(d(x0)) | → | Wait(Right15(x0)) | 
| Right1(a(End(x0))) | → | Left(b(b(b(b(b(b(End(x0)))))))) | 
| Right2(a(a(End(x0)))) | → | Left(b(b(b(b(b(b(End(x0)))))))) | 
| Right3(a(a(a(End(x0))))) | → | Left(b(b(b(b(b(b(End(x0)))))))) | 
| Right4(b(End(x0))) | → | Left(c(c(c(c(c(c(End(x0)))))))) | 
| Right5(b(b(End(x0)))) | → | Left(c(c(c(c(c(c(End(x0)))))))) | 
| Right6(b(b(b(End(x0))))) | → | Left(c(c(c(c(c(c(End(x0)))))))) | 
| Right7(c(End(x0))) | → | Left(d(d(d(d(d(d(End(x0)))))))) | 
| Right8(c(c(End(x0)))) | → | Left(d(d(d(d(d(d(End(x0)))))))) | 
| Right9(c(c(c(End(x0))))) | → | Left(d(d(d(d(d(d(End(x0)))))))) | 
| Right10(b(End(x0))) | → | Left(d(d(d(d(End(x0)))))) | 
| Right11(c(End(x0))) | → | Left(a(a(End(x0)))) | 
| Right12(c(c(End(x0)))) | → | Left(a(a(End(x0)))) | 
| Right13(c(c(d(End(x0))))) | → | Left(a(a(End(x0)))) | 
| Right14(c(c(d(d(End(x0)))))) | → | Left(a(a(End(x0)))) | 
| Right15(c(c(d(d(d(End(x0))))))) | → | Left(a(a(End(x0)))) | 
| Right1(a(x0)) | → | Aa(Right1(x0)) | 
| Right2(a(x0)) | → | Aa(Right2(x0)) | 
| Right3(a(x0)) | → | Aa(Right3(x0)) | 
| Right4(a(x0)) | → | Aa(Right4(x0)) | 
| Right5(a(x0)) | → | Aa(Right5(x0)) | 
| Right6(a(x0)) | → | Aa(Right6(x0)) | 
| Right7(a(x0)) | → | Aa(Right7(x0)) | 
| Right8(a(x0)) | → | Aa(Right8(x0)) | 
| Right9(a(x0)) | → | Aa(Right9(x0)) | 
| Right10(a(x0)) | → | Aa(Right10(x0)) | 
| Right11(a(x0)) | → | Aa(Right11(x0)) | 
| Right12(a(x0)) | → | Aa(Right12(x0)) | 
| Right13(a(x0)) | → | Aa(Right13(x0)) | 
| Right14(a(x0)) | → | Aa(Right14(x0)) | 
| Right15(a(x0)) | → | Aa(Right15(x0)) | 
| Right1(b(x0)) | → | Ab(Right1(x0)) | 
| Right2(b(x0)) | → | Ab(Right2(x0)) | 
| Right3(b(x0)) | → | Ab(Right3(x0)) | 
| Right4(b(x0)) | → | Ab(Right4(x0)) | 
| Right5(b(x0)) | → | Ab(Right5(x0)) | 
| Right6(b(x0)) | → | Ab(Right6(x0)) | 
| Right7(b(x0)) | → | Ab(Right7(x0)) | 
| Right8(b(x0)) | → | Ab(Right8(x0)) | 
| Right9(b(x0)) | → | Ab(Right9(x0)) | 
| Right10(b(x0)) | → | Ab(Right10(x0)) | 
| Right11(b(x0)) | → | Ab(Right11(x0)) | 
| Right12(b(x0)) | → | Ab(Right12(x0)) | 
| Right13(b(x0)) | → | Ab(Right13(x0)) | 
| Right14(b(x0)) | → | Ab(Right14(x0)) | 
| Right15(b(x0)) | → | Ab(Right15(x0)) | 
| Right1(c(x0)) | → | Ac(Right1(x0)) | 
| Right2(c(x0)) | → | Ac(Right2(x0)) | 
| Right3(c(x0)) | → | Ac(Right3(x0)) | 
| Right4(c(x0)) | → | Ac(Right4(x0)) | 
| Right5(c(x0)) | → | Ac(Right5(x0)) | 
| Right6(c(x0)) | → | Ac(Right6(x0)) | 
| Right7(c(x0)) | → | Ac(Right7(x0)) | 
| Right8(c(x0)) | → | Ac(Right8(x0)) | 
| Right9(c(x0)) | → | Ac(Right9(x0)) | 
| Right10(c(x0)) | → | Ac(Right10(x0)) | 
| Right11(c(x0)) | → | Ac(Right11(x0)) | 
| Right12(c(x0)) | → | Ac(Right12(x0)) | 
| Right13(c(x0)) | → | Ac(Right13(x0)) | 
| Right14(c(x0)) | → | Ac(Right14(x0)) | 
| Right15(c(x0)) | → | Ac(Right15(x0)) | 
| Right1(d(x0)) | → | Ad(Right1(x0)) | 
| Right2(d(x0)) | → | Ad(Right2(x0)) | 
| Right3(d(x0)) | → | Ad(Right3(x0)) | 
| Right4(d(x0)) | → | Ad(Right4(x0)) | 
| Right5(d(x0)) | → | Ad(Right5(x0)) | 
| Right6(d(x0)) | → | Ad(Right6(x0)) | 
| Right7(d(x0)) | → | Ad(Right7(x0)) | 
| Right8(d(x0)) | → | Ad(Right8(x0)) | 
| Right9(d(x0)) | → | Ad(Right9(x0)) | 
| Right10(d(x0)) | → | Ad(Right10(x0)) | 
| Right11(d(x0)) | → | Ad(Right11(x0)) | 
| Right12(d(x0)) | → | Ad(Right12(x0)) | 
| Right13(d(x0)) | → | Ad(Right13(x0)) | 
| Right14(d(x0)) | → | Ad(Right14(x0)) | 
| Right15(d(x0)) | → | Ad(Right15(x0)) | 
| Aa(Left(x0)) | → | Left(a(x0)) | 
| Ab(Left(x0)) | → | Left(b(x0)) | 
| Ac(Left(x0)) | → | Left(c(x0)) | 
| Ad(Left(x0)) | → | Left(d(x0)) | 
| Wait(Left(x0)) | → | Begin(x0) | 
| a(a(a(a(x0)))) | → | b(b(b(b(b(b(x0)))))) | 
| b(b(b(b(x0)))) | → | c(c(c(c(c(c(x0)))))) | 
| c(c(c(c(x0)))) | → | d(d(d(d(d(d(x0)))))) | 
| b(b(x0)) | → | d(d(d(d(x0)))) | 
| c(c(d(d(d(d(x0)))))) | → | a(a(x0)) | 
| Begin(a(a(a(x0)))) | → | Wait(Right1(x0)) | 
| Begin(a(a(x0))) | → | Wait(Right2(x0)) | 
| Begin(a(x0)) | → | Wait(Right3(x0)) | 
| Begin(b(b(b(x0)))) | → | Wait(Right4(x0)) | 
| Begin(b(b(x0))) | → | Wait(Right5(x0)) | 
| Begin(b(x0)) | → | Wait(Right6(x0)) | 
| Begin(c(c(c(x0)))) | → | Wait(Right7(x0)) | 
| Begin(c(c(x0))) | → | Wait(Right8(x0)) | 
| Begin(c(x0)) | → | Wait(Right9(x0)) | 
| Begin(b(x0)) | → | Wait(Right10(x0)) | 
| Begin(c(d(d(d(d(x0)))))) | → | Wait(Right11(x0)) | 
| Begin(d(d(d(d(x0))))) | → | Wait(Right12(x0)) | 
| Begin(d(d(d(x0)))) | → | Wait(Right13(x0)) | 
| Begin(d(d(x0))) | → | Wait(Right14(x0)) | 
| Begin(d(x0)) | → | Wait(Right15(x0)) | 
| Right1(a(End(x0))) | → | Left(b(b(b(b(b(b(End(x0)))))))) | 
| Right2(a(a(End(x0)))) | → | Left(b(b(b(b(b(b(End(x0)))))))) | 
| Right3(a(a(a(End(x0))))) | → | Left(b(b(b(b(b(b(End(x0)))))))) | 
| Right4(b(End(x0))) | → | Left(c(c(c(c(c(c(End(x0)))))))) | 
| Right5(b(b(End(x0)))) | → | Left(c(c(c(c(c(c(End(x0)))))))) | 
| Right6(b(b(b(End(x0))))) | → | Left(c(c(c(c(c(c(End(x0)))))))) | 
| Right7(c(End(x0))) | → | Left(d(d(d(d(d(d(End(x0)))))))) | 
| Right8(c(c(End(x0)))) | → | Left(d(d(d(d(d(d(End(x0)))))))) | 
| Right9(c(c(c(End(x0))))) | → | Left(d(d(d(d(d(d(End(x0)))))))) | 
| Right10(b(End(x0))) | → | Left(d(d(d(d(End(x0)))))) | 
| Right11(c(End(x0))) | → | Left(a(a(End(x0)))) | 
| Right12(c(c(End(x0)))) | → | Left(a(a(End(x0)))) | 
| Right13(c(c(d(End(x0))))) | → | Left(a(a(End(x0)))) | 
| Right14(c(c(d(d(End(x0)))))) | → | Left(a(a(End(x0)))) | 
| Right15(c(c(d(d(d(End(x0))))))) | → | Left(a(a(End(x0)))) | 
| Right1(a(x0)) | → | Aa(Right1(x0)) | 
| Right2(a(x0)) | → | Aa(Right2(x0)) | 
| Right3(a(x0)) | → | Aa(Right3(x0)) | 
| Right4(a(x0)) | → | Aa(Right4(x0)) | 
| Right5(a(x0)) | → | Aa(Right5(x0)) | 
| Right6(a(x0)) | → | Aa(Right6(x0)) | 
| Right7(a(x0)) | → | Aa(Right7(x0)) | 
| Right8(a(x0)) | → | Aa(Right8(x0)) | 
| Right9(a(x0)) | → | Aa(Right9(x0)) | 
| Right10(a(x0)) | → | Aa(Right10(x0)) | 
| Right11(a(x0)) | → | Aa(Right11(x0)) | 
| Right12(a(x0)) | → | Aa(Right12(x0)) | 
| Right13(a(x0)) | → | Aa(Right13(x0)) | 
| Right14(a(x0)) | → | Aa(Right14(x0)) | 
| Right15(a(x0)) | → | Aa(Right15(x0)) | 
| Right1(b(x0)) | → | Ab(Right1(x0)) | 
| Right2(b(x0)) | → | Ab(Right2(x0)) | 
| Right3(b(x0)) | → | Ab(Right3(x0)) | 
| Right4(b(x0)) | → | Ab(Right4(x0)) | 
| Right5(b(x0)) | → | Ab(Right5(x0)) | 
| Right6(b(x0)) | → | Ab(Right6(x0)) | 
| Right7(b(x0)) | → | Ab(Right7(x0)) | 
| Right8(b(x0)) | → | Ab(Right8(x0)) | 
| Right9(b(x0)) | → | Ab(Right9(x0)) | 
| Right10(b(x0)) | → | Ab(Right10(x0)) | 
| Right11(b(x0)) | → | Ab(Right11(x0)) | 
| Right12(b(x0)) | → | Ab(Right12(x0)) | 
| Right13(b(x0)) | → | Ab(Right13(x0)) | 
| Right14(b(x0)) | → | Ab(Right14(x0)) | 
| Right15(b(x0)) | → | Ab(Right15(x0)) | 
| Right1(c(x0)) | → | Ac(Right1(x0)) | 
| Right2(c(x0)) | → | Ac(Right2(x0)) | 
| Right3(c(x0)) | → | Ac(Right3(x0)) | 
| Right4(c(x0)) | → | Ac(Right4(x0)) | 
| Right5(c(x0)) | → | Ac(Right5(x0)) | 
| Right6(c(x0)) | → | Ac(Right6(x0)) | 
| Right7(c(x0)) | → | Ac(Right7(x0)) | 
| Right8(c(x0)) | → | Ac(Right8(x0)) | 
| Right9(c(x0)) | → | Ac(Right9(x0)) | 
| Right10(c(x0)) | → | Ac(Right10(x0)) | 
| Right11(c(x0)) | → | Ac(Right11(x0)) | 
| Right12(c(x0)) | → | Ac(Right12(x0)) | 
| Right13(c(x0)) | → | Ac(Right13(x0)) | 
| Right14(c(x0)) | → | Ac(Right14(x0)) | 
| Right15(c(x0)) | → | Ac(Right15(x0)) | 
| Right1(d(x0)) | → | Ad(Right1(x0)) | 
| Right2(d(x0)) | → | Ad(Right2(x0)) | 
| Right3(d(x0)) | → | Ad(Right3(x0)) | 
| Right4(d(x0)) | → | Ad(Right4(x0)) | 
| Right5(d(x0)) | → | Ad(Right5(x0)) | 
| Right6(d(x0)) | → | Ad(Right6(x0)) | 
| Right7(d(x0)) | → | Ad(Right7(x0)) | 
| Right8(d(x0)) | → | Ad(Right8(x0)) | 
| Right9(d(x0)) | → | Ad(Right9(x0)) | 
| Right10(d(x0)) | → | Ad(Right10(x0)) | 
| Right11(d(x0)) | → | Ad(Right11(x0)) | 
| Right12(d(x0)) | → | Ad(Right12(x0)) | 
| Right13(d(x0)) | → | Ad(Right13(x0)) | 
| Right14(d(x0)) | → | Ad(Right14(x0)) | 
| Right15(d(x0)) | → | Ad(Right15(x0)) | 
| Aa(Left(x0)) | → | Left(a(x0)) | 
| Ab(Left(x0)) | → | Left(b(x0)) | 
| Ac(Left(x0)) | → | Left(c(x0)) | 
| Ad(Left(x0)) | → | Left(d(x0)) | 
| Wait(Left(x0)) | → | Begin(x0) | 
| a(a(a(a(x0)))) | → | b(b(b(b(b(b(x0)))))) | 
| b(b(b(b(x0)))) | → | c(c(c(c(c(c(x0)))))) | 
| c(c(c(c(x0)))) | → | d(d(d(d(d(d(x0)))))) | 
| b(b(x0)) | → | d(d(d(d(x0)))) | 
| c(c(d(d(d(d(x0)))))) | → | a(a(x0)) |