A system comprising a light fixture (100, 200), the light fixture comprising: - at least one visible light source (109, 209) emitting visible light, - at least one IR light source (119, 219) emitting infrared light in an infrared spectrum, - an outer housing in which the at least one visible light source and the at least one IR light source are located, - a first projection system configured to collect at least some of the visible light and configured to generate at least one first light beam (113, 213) of the visible light along an optical axis having a first beam characteristic, - a second projection system configured to collect at least some of the infrared light and configured to generate at least one second light beam (121, 221) of the IR light along the optical axis, wherein the second projection system is configured such that at least outside the outer housing the second beam characteristic substantially corresponds to the first beam characteristic, - characterized by further comprising a control unit configured to determine a control signal to be emitted by the at least one IR light source through the second light beam, the control signal including encoded control information for controlling a light source of a receiving unit receiving the control signal, the system comprising a plurality of response units, each response unit comprising at least one IR receiver configured to receive the second light beam and at least one light source emitting light in the visible range, wherein light sources of the plurality of response units which are illuminated by the first and second light beams are controlled in accordance with the control signal contained in the at least one second light beam. - at least one visible light source (109, 209) emitting visible light, - at least one IR light source (119, 219) emitting infrared light in an infrared spectrum, - an outer housing in which the at least one visible light source and the at least one IR light source are located, - a first projection system configured to collect at least some of the visible light and configured to generate at least one first light beam (113, 213) of the visible light along an optical axis having a first beam characteristic, - a second projection system configured to collect at least some of the infrared light and configured to generate at least one second light beam (121, 221) of the IR light along the optical axis, wherein the second projection system is configured such that at least outside the outer housing the second beam characteristic substantially corresponds to the first beam characteristic, - characterized by further comprising a control unit configured to determine a control signal to be emitted by the at least one IR light source through the second light beam, the control signal including encoded control information for controlling a light source of a receiving unit receiving the control signal, the system comprising a plurality of response units, each response unit comprising at least one IR receiver configured to receive the second light beam and at least one light source emitting light in the visible range, wherein light sources of the plurality of response units which are illuminated by the first and second light beams are controlled in accordance with the control signal contained in the at least one second light beam.