The PCWs were not designed to play video games, although some software authors considered this a minor detail, releasing games like "Batman", "Head Over Heels", and "Bounder". The PCW video system was not at all suited to games. In order that it be able to display a full 80-column page plus margins, the display's addressable area was 90 columns and the display had 32 lines. The display was monochrome and bitmapped with a resolution of 720 by 256 pixels. At 1 bit per pixel, this occupied 23 KB of RAM which was far too large for the Z80 CPU to scroll in software without ripple and tearing of the display. Instead, the PCW implemented a Roller RAM consisting of a 512-byte area of RAM that held the address of each line of display data. The screen could now be scrolled either by changing the Roller RAM contents or by writing to an I/O port that set the starting point in Roller RAM for the screen data. This allowed for very rapid scrolling. The video system also fetched data in a special order designed so that plotting a character eight scan lines high would touch eight addresses. This meant that very fast Z80 copy instructions like LDIR could be used. Unfortunately, it also meant that drawing lines and other shapes could be very complicated.