Where is Philip K. Dick's head?

They don't make stories much weirder than this:

• A guy makes a robot that looks like sci-fi writer Philip K. Dick.
• The robot makes appearances at comic book conventions and other events.
• The robot's head vanishes somewhere between Las Vegas and San Francisco.
• The renegade head dismays its maker, offers hope to those who subscribed to Dick's world view.
  

It's all in this NYT article.