In the inner courtyard of this prison there was a statue symbolising the punishment of the inmates of this house of correction. A similar reference to punishment can be seen on the old gateway entrance to the Rasphuis prison, which today is one way into the shopping mall called the Kalvertoren. At the end of the 16th century for the first time people were punished by being locked up. The prisoners had to work to earn their keep. One type of employment was shredding wood, including Brazilian timber. The city of Amsterdam held the monopoly on this. The chippings and sawdust were delivered to paint factories where they were boiled to produce red dye. The new penal system thus provided the city with cheap labour. The House of Correction, as befitted the Dutch commercial spirit, was also a profit-making business.