Abstract: A device for variably covering an area includes a first shade and a first driver. The first shade includes a first roller, a first draw bar, and a first curtain. The first roller is configured for mounting in a first fixed position. The first curtain has one end connected to the first roller and another end connected to the first draw bar. The first curtain is windable on the first roller to uncover the area and unwindable from the roller to cover the area. The first draw bar includes two ends, and the first driver is connected to the two ends for evenly pulling the first draw bar away from the first roller and unwinding the first curtain.