S -> aS | b L(G) = {anb | n ∈ ℕ, n > 0}
S -> aBa B -> aBa | b L(G) = {an b a^n | n ∈ ℕ, n > 0}
S -> aSBC S -> aBC CB -> BC aB -> ab bB -> bb bC -> bc cC -> cc
L(G) = {an bn c^n | n ∈ ℕ, n > 0}
