NicoWall is a wallpaper management application.It change the wallpaper automatically with images of NicoNicoSeiga ( http://seiga.nicovideo.jp ).It’s not require account of NicoNicoDouga, you only have to choice your favorite ‘Clip’ .(‘Clip’ is a feature of NicoNicoSeiga like photo album)Of course you have account, you can create your own Clip.