OK, I can't help myself here.
For those who just walked in, protomics was the name of the fictional in-universe technology I created for Flight of the Vajra, where various forms of matter have been created that are programmable and malleable. (I started writing that story over three years ago.)
The researchers call the building blocks "catoms" (or "claytronic atoms"), but even the concept as they describe it is fundamentally the same as what I had in mind:
... the researchers hope to use a set of local rules, whereby each catom needs to know only the positions of its immediate neighbors. Properly programmed, the ensemble will then find the right configuration through an emergent process.
... The researchers’ ultimate aim is to create a system of modules the size of sand grains that can form arbitrary structures with a variety of material properties, all on demand.
And at the bottom is this cute scare headline: "Help, My Chair Has a Virus! / Hackers could turn your programmable matter against you." (Yep, that's in the book too.)
I kick myself now for not putting in that patent application ahead of time.
Well, I had a feeling something like this would come along in some form; it didn't have to be as I predicted it, or on anything like the same time scale. I gave it a century or so from "now" before it really took off; I still give it a good long time before it's on the scale I had in mind.
But I have to reiterate that the point of the book wasn't to predict any specific thing or even enumerate how workable a given concept would be. Protomics, the "entanglement drive", the whole far-future¹ setting I devised was just a backdrop for a story about some people who are faced with some very tough choices, whose lives (and the lives of innumerable others) are altered because of that, and who can only see it all through by turning to each other. In the end, the human side of the story had to win, and I hope it did.
Addendum: DARPA has something tangentially related: "Atoms to Product: Aiming to Make Nanoscale Benefits Life-Sized".
¹ I almost typed "fart-future". I almost kept it.