Art Q&A > Architecture > Screenwalls > Screenwall ABC Advanced Search E-Mail This Article Print Friendly Format Screen Walls and Siheyuan Screen walls are a common feature of the courtyard-style houses in Beijing and other ancient towns. One of their original functions was to frustrate nosey passers-by and allow people in the courtyards a little privacy. Another, no less important function of these walls was to frustrate something far more insidious: evil spirits. According to Chinese superstition, malevolent ghosts and devils can only move in straight lines. Thus a wall built just inside the door of a home would keep out any unwanted otherworldly visitors while presenting only a minor inconvenience to the living inhabitants, who could simply walk around it.