Is it an arse or an elbow?

And now for a quick commercial break.

Look at each picture. Is it an arse or an elbow?

This fun little waste of time I mean quiz brings up a point I talk about in my classes. How we as humans or viewers are very willing to meet an image half way and well fill in the missing or vague part of the picture. This well help to define what type of fine art connoisseur you are and where your tastes lay.

So, what is it arse or elbow?
http://www.zegelin.com/love_files/ArseorElbow.htm#_clouds paintings