proscenium while retaining the utility of a backstage area. Entrances onto a thrust are most readily made from backstage, although some theatres provide for performers to enter through the audience using vomitory entrances. An arena, exposed on all sides to the audience, is without a backstage and relies entirely on entrances in the house or from under the stage. As with an arena, the audience in a thrust stage theatre may view the stage from three or more sides. If a performance employs the fourth wall, that imaginary wall must be maintained on multiple sides. Similar to theatre in the round, the audience can view the performance from a variety of perspectives, and as such it is usual for the blocking, props and scenery to receive thorough consideration to ensure that no perspective is blocked from view. A high backed chair, for instance, when placed stage right, could create a blind spot in the stage left action. Black box A black box theater consists of a simple yet somewhat unadorned performance space, ideally a large square room with black walls and a flat floor, which can be used flexibly to create a stage and audience area. Created and found spaces A stage can also be improvised wherever a suitable space can be found. Examples may include staging a performance in a non traditional space such as a basement of a building, a side of a hill or, in the case of a busking troupe, the street. In a similar manner, a makeshift stage can be created by modifying an environment. For example, demarcating the boundaries of a stage in an open space by laying a carpet and arranging seating before it. The theater company Shakespeare In The Park, in fact, is based around performing Shakespeare plays in a space that one wouldn't likely find it, namely, Central Park in New York City. Stage terminology The stage itself has been given named areas to facilitate the precise movement and positioning of actors on a stage (see Blocking (stage)). To an actor facing the audience, "left" and "right" are the reverse of what they are for the audience. To prevent confusion, actors and directors never use the unmarked terms left or right for the sides of the stage. Rather, they use a phrase specifying the viewpoint. The terms "stage left" and "stage right", respectively, denote the sides of the stage that are