A curtain is a piece of cloth or other material intended to block or obscure light, air drafts. A curtain is also the movable screen or drape in a theatre that separates the stage from the auditorium or that serves as a backdrop or background. Curtains are often hung on the inside of a building's windows to block the passage of light. For example, at night to aid sleeping or to stop light from escaping outside the building. In addition, Curtain also use for purpose of privacy that stopping people outside from being able to see inside.