The word didactic is defined as information designed or intended to teach or sometimes teaching, with the ulterior motive for moral instruction. In terms of projection design this can be accomplished quite easily and was first embraced by Erwin Piscator and Bertolt Brecht in 1920's Germany. Didactic projections can take the form of a variety of mediums but it should be understood that whatever that is it should be in someway a reflection of reality. The reality that the play is trying to expose and use that information to fuel the meaning of the work. Projections does this easily by employing techniques that can derivative of the news (Newspapers, Broadcast television, Newsreels), political concepts, instructional information, and anything that can give historical context. Often times text is employed but also iconic imagery that can be easily reconizeable within the context of understanding a time period.
It is in this context that many playwrights will write these images into the script it helps to offer a window to the issues important of the times. Using facts to support an argument similar to how a new program may use information to not only report an event but also to promote a perspective. For example the play columbinus draws on the images of the events surrounding the incident to put the audience in the feeling of someone watching the events unfold in front of them. Didactic imagery is often used in shows that deals with social and political issues and gives credibility to stance the play presents as its perspective. In a simpler manner they can also either be presentations given by characters or survailence video from a live feed.