DOLANAC (ドラナク) is a mahjong computer game which pits the player against one of several female characters. These characters resemble six girls from the series Saki: Saki Miyanaga, Nodoka Haramura, Kana Ikeda, Mihoko Fukuji, Koromo Amae and Momoko Touyoko. The character Switch can be seen playing against is named "Nodocchi" - which is Nodoka Haramura's nickname.
Additionally, the positioning of characters on the cover is near identical to the package for the CLANNAD game and "DOLANAC" is only one letter off from being an anagram of CLANNAD.