In most theaters, a main drape is closed as the audience walks in, only to be opened when the house lights dim and the performance starts. Staring at a blank curtain or drop would be incredibly boring, so theater techs usually diagonally focus some ellipsoidals across the fabric, striping it with patterns of light. It gives the stage a warmer look and the audience something to look at. Gobos are often utilized in the light fixtures.
—Nook Schoenfeld, from PLSN, April 2018, page 73
