For advertising purposes, advertising messages in the form of printed sheets of paper or the like are set into acrylic glass (perspex) or other blocks of transparent material which can be cast or formed in another way. To make these advertising messages more conspicuous, light guides are set into the blocks, which take up light at the broad sides and emit it only at the end faces. Advertising messages can be written on or printed films can be glued to the end faces. This gives the viewer of the block the impression that the writing is self-illuminating or that the block is illuminated from inside, and the advertising writing becomes more conspicuous.
