The term has been associated with ubiquitous games, augmented and mixed reality games, mobile games, alternate reality games, (enhanced) live action role playing, affective gaming, virtual reality games, smart toys, location-based or location-aware games, crossmedia games and augmented reality tabletop games.[2] The book Digital Cityscapes categorizes "playful activities that use mobile technologies as interfaces and the physical space as the game board" into four categories; pervasive games is said to be the most general, with urban games, location-based mobile games and hybrid reality games being successively more specific.[6]