I must have seen this fabulous painting hundreds of times before I started to wonder at what the wierd white baton on the carpet was.

If you bend down to the left and look up at the painting obliquely it becomes a skull.

(For anyone who might be interested this distortion is called an anamorphosis )

What was he at?
I know several doctrinal theses have been written to explain the symbols in this painting but I remain unsure of his intentions.

Maybe that is just what he intended.