Programmable pigments: Photochromic nanoparticle inks for rewritable tattoos

Hear me out, implanted lie detectors with displays tattooed into the foreheads of politicians.

I'll have to read up on this. I wonder about it as a kind of e-ink?

I'm sure there are a bunch of differences, but fun to think about perhaps.

That is so cool. I wonder if this allows for printing images with some kind of 3d printer like thing with a weak uv laser