Fur

One of the great painting challenges is depicting fur. Its one thing to do it with line and humor, as above, but its another to do it in paint. At the Frick Museum there are three fantastic examples: a Titian portrait , a Vermeer, and a Rembrandt. Every time I go I spend time with my nose right up to the paintings trying to understand the mush of brushwork that becomes tangible, visceral fur when you step back.
In the painting below--the fur isn't bad, although the painting itself isn't one of my favorites:
...Sphinx fur detail: