tableau curtains → διαγώνια αυλαία
The tableau, tab, or tabbed curtain, also called opera drapes, though iconic of the theater setting, is the rarest of curtains to actually be employed on the stage. It has two overlapping panels (often but not always pleated) immovably secured at the top, to a fixed batten. Each panel is sewn with a more-or-less diagonal series of rings, running from the upper offstage corner to the onstage-most side, either midway down or lower. A line or cable attaches to the lowest ring, runs diagonally offstage through the other rings, through a pulleys on the batten, then down to the floor. When the lines are pulled, each curtain is lifted diagonally offstagewards and out (upwards). In its open position it creates a frilled, tent-like viewing frame for the performance, like an inner proscenium arch: a top "scallop" with the rest of the curtain gathered at the sides (replacing the foremost fixed side curtains often used with other curtain types).
Front curtain - Wikipediatableau curtain - Wiktionary