User blog comment:KurohaKafka/Turing-incomplete/@comment-25601061-20171027234156

Ξ[I](x) = x (using III... with x I's)

Ξ[K](x) = x (using KKK... with x K's)

Ξ[S](1) = 1 (using S)

Ξ[S](2) = 2 (using SS)

Ξ[S](3) = 3 (using SSS)

Ξ[S](4) = 4 (using SSSS)

Ξ[S](5) ≥ 6 (using SSS(SS) -> S(SS)(S(SS)))