I'm not sure if it's useful in this incarnation, but I am reminded of the localizers in A Deepness in the Sky, an early description of smartdust which were rela

I'm not sure if it's useful in this incarnation, but I am reminded of the localizers in A Deepness in the Sky, an early description of smartdust which were relatively omnipresent and capable of communicating and being reprogrammed by light patterns.