Why do they do it?

Cat's often sleep with a paw covering their nose or eyes.  There are lots of theories about why they do it.  One is that they are just keeping their nose warm or blocking out light to their eyes.  Another says it is a way to feel safe and secure, but my favorite is it is a cat's way of hanging a sign out that says, "Do not disturb!"  Well, there will be no disturbing today as a rainy day is forecasted.  A good day for a book and, maybe, a nap!