YES

2 decompositions
 #1 -----------
   1: W(W(x1)) -> W(x1)
   2: B(I(x2)) -> W(x2)
   3: W(B(x3)) -> B(x3)

 #2 -----------
   4: F(H(x4),x5) -> F(H(x4),G(x5))
   5: F(x6,I(x7)) -> F(G(x6),I(x7))
   6: G(x8) -> x8

@Knuth and Bendix' criterion
--- R
   1: W(W(x1)) -> W(x1)
   2: B(I(x2)) -> W(x2)
   3: W(B(x3)) -> B(x3)

--- S
   1: W(W(x1)) -> W(x1)
   2: B(I(x2)) -> W(x2)
   3: W(B(x3)) -> B(x3)


@Development Closedness
--- R
   4: F(H(x4),x5) -> F(H(x4),G(x5))
   5: F(x6,I(x7)) -> F(G(x6),I(x7))
   6: G(x8) -> x8

--- S
   4: F(H(x4),x5) -> F(H(x4),G(x5))
   5: F(x6,I(x7)) -> F(G(x6),I(x7))
   6: G(x8) -> x8