More or less, that's what Game of Life was intended to illustrate. Extremely complex systems can, and often do, evolve from a few seemingly simple rules. This sorta takes the "spontaneity" out of the more fanciful versions of the origins of life, instead rendering life the inevitable outcome of given circumstances. This is why we think we can detect^1 life in the universe, if it exists without actually travelling to other planets.

1. aka "make educated guesses with a good degree of certainty"

Only a few rules are necessary for complexity.

In ALife systems (Conway etc).

In Fractals (Mandelbrot etc).

In random number generation (Mersenne Twister etc)

Maybe, in the big picture, complexity is trivial to create.

Then also trivial to characterize, to analyze, perhaps also to unwind ?

Well they do call it "complexity".