Or even an architecture akin to an atonishingly large number of RP2050's. It does seem like it would work well for certain types of nnet architectures.

I've always been partial to the idea of two parallel surfaces with optical links, Make a connection machine style hypercube where the bit of the ID of every processor indicates its location in the hypercube. Place all of the even parity CPUs on one surface and the odd parity CPUs on the other surface, every CPU would have line of sight on its neighbour in the hypercube (as well as the diametrically opposed CPU with all the ID bits flipped)