Sometimes are permanent parts of the building rather than curtains trap, trap room: a trap is a hole in the stage floor. Sm console: a desk containing communication systems and houselight / worklight controls used by the stage manager. Located in the control booth in modern theatres, located in the wings in older theatres. In present practice, stage managers call the show from a position behind the audience structural grid: a structural grid is integral to the structure of a building, and capable of bearing large loads. Counterweight fly system: has a mechanism to easily add counterweights to balance scenery loads. Lx or electric: a pipe or batten that is equipped with electrical outlets for lights shin: a temporary lighting position that puts a light on the floor in the wings. Boom - a permanent or temporary lighting position attatched to a wall spot bay, spot box, spot chair: positions in the auditorium where follow spots can be located.