Abstract: In order to be able to realistically display and imitate the presence of humans and/or animals in a building with simple, inexpensive means, it is provided that the intensity of the radiated light of at least one group of adjacent light sources is reduced relative to the intensity of the radiated light from light sources of the arrangement outside of the at least one group in order to imitate a shadow on a wall illuminated by the security device and further light sources are added to at least one group and/or light sources of the at least one group are removed from the same and the intensity of the radiated light of an added light source is reduced and the intensity of a remote light source is increased in order to imitate a movement of the shadow.