> Generically, reductions stronger than polynomial-time reductions are used, since all languages in P (except the empty language and the language of all strings) are P-complete under polynomial-time reductions.

[1] https://en.wikipedia.org/wiki/P-complete

Do you think there is an "obvious" way to simulate the lambda calculus using origami crease patterns more directly? For example, a cyclic tag system or even rule 110 configuration simulating the lambda calculus without indirection through Turing machines.