From November 1940, some prisoners were trained as stonemasons in a specialized workshop; their numbers reached 1,200 by December 1942. The prisoners were instructed by civilian experts in a ten-week course covering both practical and theoretical topics, but watched carefully by kapos. Those who failed to advance were sent to work in the quarries, while those whose productivity improved were given cigarettes and extra food. The stone that they cut was used for construction of the camp, the "Autobahn", and various SS military projects, but later on it was destined for the monumental German Stadium project and the Nazi party rally grounds in Nuremberg.