[brianberns]

He doesn't mention it, but this is basically what we today call "SKI" combinators: https://en.wikipedia.org/wiki/SKI_combinator_calculus

* I is the identity function: Ix = x

* K is the constant function: Kxy = x

* S is a bit more complex: Sxyz = xz(yz)

[arethuza]

And, of course, the Y-combinator which provides recursion:

Y = S(K(SII))(S(S(KS)K)(K(SII)))

https://en.wikipedia.org/wiki/Fixed-point_combinator