It turns out the “Arabic writing” is neither Arabic nor writing, and scarcely resembles Arabic writing. Rather, it looks like a stylized drawing of a sword.
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UPDATE: I forgot to mock the people who think there are mysterious Arabic symbols. Arabic is a language. It has writing. There are no Arabic symbols. So no job for a Tom-Hanks-style Dan Brown mystery Angels and Demons kind of *symbologist*, more’s the pity.
Anonymous Arabist وين الناس 
Even to say “a sword” is to follow too much in the footsteps of that unbelievably idiotic Fox broadcast.
Most of the marks were parallel scratches — possibly even mechanical in origin. The thing with a crossbar you could even call … a Cross. Or a “t” as in… “terrorism”?… “Texas”! That’s it ! Evil subliminal messages from Rick Perry !!!
Good point, Peter!