Picture is here (from last year): https://www.nature.com/articles/s41550-021-01585-9 https://www.nature.com/articles/s41550-021-01585-9 Looks a little like cof

Picture is here (from last year): https://www.nature.com/articles/s41550-021-01585-9 https://www.nature.com/articles/s41550-021-01585-9 Looks a little like coffee grounds in a grinder, only if you ground charcoal.