The art of mathematics in chalk: https://www.scientificamerican.com/article/the-art-of-mathematics-in-chalk/
Teaser for the forthcoming book Do Not Erase: Mathematicians and Their Chalkboards, featuring several photographic spreads of chalkboard illustrations and formulas and their explanations.
They appear to be mostly set-ups rather than captured from active research, but still pretty and interesting. I linked an earlier post on this in 2019 (https://mathstodon.xyz/@11011110/102856920767696508) but with fewer photos and no explanations.
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