Willem van der Sluis (1972) designed a demountable and moveable sports and recreation facility at the detention centre in Zaandam. Asylum seekers who have been denied residence are held here awaiting deportation. Van der Sluis based his design on the classical dome construction. The fencing material has a pattern which filters the light as the leaves of a tree do in nature. At night the ‘sportdomes’, as Van der Sluis calls them, are transformed into beacons of light that point at the hopeless situation of the inhabitants of the center.