The use of screens in drama 

Plays have a history of using visual trickery to obscure specific identities while presenting action. Ancient Greek actors wore masks and voluminous robes, and Jacobian theatre's often elaborate costuming and stage design elevated the drama's spectacle by occluding the performers. Technology has changed over the centuries, but the techniques remain similar. The best illusions spring from the simplest ideas. On the modern stage, silhouette screens add both mystery and visual appeal. In essence, this technique uses a screen lit from behind. Whatever appears between the light and screen is rendered visible to the audience as pure shadow.