Is it a woman?  Is it a cow?  Is it a baboon?  We will never know, because enigmatic artist Pablo Picasso took the answer to the grave with him, having never visited Chicago or seen the work he graced the city with. But this month is the 50th anniversary of the erection of Picasso’s gift to the city in what was then called Civic Center Plaza.  Ever since, tourists and locals have gazed into its narrow-set eyes and puzzled at what it might represent. When the statue was unveiled in 1967, some people thought it was an Afghan dog.  Picasso had pet Afghans.  But he also had a muse.  A November, 2004...