An apparatus for image data computation and for synchronous data output. An arrangement for producing and reproducing two partial light images which together can be perceived as a light image having a three-dimensional effect. A method of synchronous reproduction of time image sequences by at least two image reproduction devices. The apparatus according to an embodiment of the present invention has a master-client structure. A graphics master unit and at least two graphics clients are connected together by way of a first message channel and by way thereof exchange first messages, such that computation and projection of the partial images is synchronized.