Outside tools are not required.

We'll selectively breed humans until one can just compute it in...meat[0].

https://www.youtube.com/watch?v=7tScAyNaRdQ

You don't need to flip gradients, just need to train the monkeys to operate matchboxes: https://en.wikipedia.org/wiki/Matchbox_Educable_Noughts_and_...

Reminds of that part in the Three-Body Problem novel where the emperor of the videogame builds a CPU with soldiers as bits