Seriously, How Does This Work?

I often brag to other bloggers that I have the sharpest readership on the web.  Let's put that to the test.

Check out these guys.  I saw them on Ponte Sant'Angelo (the bridge over the Tiber that leads to Castel Sant'Angelo) the other day, and everyone who passed by was mesmerized.  I even threw them a euro.  I certainly don't know how they do it.  And I don't think anyone else I saw gawking knew either.

Here's a pic.  There's no need for a live-action video here.  The guys stay perfectly still just in the way they are depicted here:

Does anybody out there know?  How is this done?

Historical Aside:  The Castel Sant'Angelo is on the Vatican side of Rome.  The castle was completed in 139 A.D., and is a 10-minute walk from St. Peters.  (It is also featured prominently in Dan Brown's Angels and Demons.)  The Ponte Sant'Angelo leading to it has to be the best of the little bridges over the Tiber.  With all of the little statues on the sides -- and with the castle as a backdrop -- it's really kind of spooky.  It is reminiscent of the Charles Bridge in Prague, albeit on a smaller scale.

I promise a better picture at some point on a day when it's not so crowded.