There was a punishment cell in each prison. Prisoners seen as recalcitrant were isolated in total darkness, chained to a ring in the middle of the cell. Sometimes (for example at Aiud) they were kept with their legs tied to a grill under water. The prisoner was incarcerated naked and barefoot. His food ration was reduced to half. In the dark, cold and hungry, he was forced to remain on his feet all day and all night.