Dan Foreman-Mackey opined that the main thing I was communicating with my ur-complex probabilistic graphical model for stars and Gaia is it's complicated. So I built a simplified pgm, crushing all the stellar physics into one node, with the intention of blowing up that node into its own model in a separate figure.
I had a great conversation at lunch with David Weinberg (OSU) about stellar chemical abundances, and in particular whether we could show that chemical diversity is larger than can be explained with any model in which supernovae ejecta get fully mixed into the ISM. He pointed out that while there does appear to be diversity among stars, in certain directions the diversity of abundance ratios is extremely tiny; in particular: Although the alpha/Fe distribution is bimodal, at any Fe/H, the two modes are both very narrow! That's super-interesting.