Answer:
It is called a Gobo
Explanation:
Gobo is a technique in photography and film used to block the lighting using a screen, stencil or template that is placed inside or in front of a light source, in order to produce different shapes in the lighting. It's often used with stage lighting instruments to manipulate the shape of the light projected over a space or object, and cast different shapes or patterns. In theatrical lighting, the term refers to a device placed between the light source and the lenses or other optics to produce a sharp edge pattern or design.
