The missing elements in the diagram on the Wikipedia page for List of cetaceans is missing some line-art of various whales and such. Where the art is missing, the box simply bears the legend "cetacean needed." (ObRef XKCD)
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.