Clepsydra , a term used in Treblinka extermination camp , means `` water clock '' in Greek .
If a prisoner was beaten and sustained black eyes , open wounds and severe swelling , he was called a clepsydra ( Polish for `` obituary '' ) by the other prisoners and most likely shot that evening at roll call or the next day if the bruised cheeks began to swell up .
Treblinka extermination camp