If anything, British artist Banksy is known for his mordant wit. On the heels of his “Cardinal Sin” sculpture at Liverpool’s Walker Art Gallery, Banksy has unveiled a new work, “Fallen,” that depicts the fractured remains of a Roman soldier statue. Is it a statement about crumbling empires in the New World Order? A polemic against classical art forms? A general argument in favor of destroying the old to make way for the new? Meanwhile, the presence of a ridiculously mundane “Caution Wet Floor” sign suggests slapstick comedy over social commentary, though with the mercurial Banksy no one can know for sure.