Bloodshot faces, baked into ceramic pots, grimace in pain. Gnarled fingers poke from ashen clay. A skull and hands, the only remains of a body, grip the top of a wall, trying to escape. They are among more than 100 pieces created by Francisco Toledo, perhaps Mexico's most famous living artist, for his "Mourning" exhibit, a memorial to the country's recent mass killings and disappearances, including 43 students from the Ayotzinapa teacher training…