The prisoners probably smear the stuff on the walls themselves. Or while throwing it at the guards miss and hit the walls instead. That's what they do down in Guantanamo Bay. It's a cultural thing, as I understand it.
In his three years at Guantanamo Bay, Cuba, Abdul Rahim Muslim Dost invented ways to write poetry. Dost, 44, read from his works recently at his home in Peshawar, Pakistan. (Declan Walsh for the Boston Globe)
I write this for Allah, moon-god:
Though you Westerners think it is odd
If this poetry sells
I can kill infidels
Derka Derka, Mohammed, jihad!