Interaction is a unique mechanic that is connected not so much with the in-game progression itself (gain something by doing something and then again) as with the contemplation of the game (an ability to observe what was gained). Every element becomes valuable not only within the game itself but also on its own. The types of interaction can vary significantly depending on the setting (for instance, feeding, petting, or washing the pet), thus interaction is one of the most creative and easy-to-design mechanics. Various interactions can be matched with almost any item, except for points.