Black and white are the default background colors for many of my photos. There are several background systems (paper, fabric, roller blinds, etc.) and I wanted to have something that is easily changeable, portable and inexpensive for those two colors.
The result is a background wall on wheels. Both sides are papered with background-wallpaper and so they are easily repaintable. By default I have one of the sides painted white and the other painted black.
Size-wise the wall is 2m high and 1.8m wide, so I have enough space for portraits and full body images. The wall stands safely on its attached furniture castors and is still very mobile in space.