The
borders
Borders are short drapes hung above the stage, spanning its width. During the assembling, they are attached to poles which are supported by the grid. They are made from a velour light-absorbing fabric to mask from the audience the backstage, spotlights, poles, and other technical equipment.
Borders, legs, and the cyclorama frame the stage to create a “black box”. They can be neutral or sometimes be included in the set.