I think it might help to talk here more about co-occurance, why it's important, maybe some examples of it used in the wild?

do you have ideas where to find examples? i was kind of hoping this would be an example. i agree on giving a short overview

Maybe @allisonhorst you have some suggestions? I know its used a lot in the NLP space, but I don't have a great go-to example on hand...

Here's a recent example on co-occurrence of Covid-19 symptoms: https://kieranhealy.org/blog/archives/2020/04/16/upset-plots/. I think this nicely highlights failures of Venn Diagrams, so could be useful in setting up clearer ways to visualize co-occurrence w/ more complex datasets. + I love a good UpSet plot.

I think it might be good to start the graph with a default filter, one that doesn't have so much overflow. (I also think there's ways we could tweak the simulation parameters to make this happen less.)

done!

It might help with accessibility to add that Plot colorContrast helper - not sure though if you want to add that level of complexity though. https://observablehq.com/@observablehq/plot-colorcontrast-custom-transform?collection=@observablehq/plot-examples

actually that's a really nice addition to the matrix visualization tutorial (importing an improvement and applying it)