Pets have long been regarded as human companions. Playing with cats and dogs was one of the most primitive ways of ‘play’ throughout mankind’s history, yet the anthropocentric perspective on the house has not changed. Starting from the co-existence of pets and people, the project tries to define the strategies for how cats can play with people in the house. By looking at the house from the ‘Cats Eye View’, it will achieve a new way of thinking that embodies a playful partnership between cats and people. Respecting the behavior and scale of cats, the project focuses on the potential of unused spaces in conventional houses. So-called ‘Cat Scale’ spaces, such as under the bed, upon the bookshelves, or near the ceiling, can be used as playgrounds where cats and people can enjoy together. Playful spaces are thus shared by two user groups of different scales and lifestyles, creating a visionary hint of harmonious living; and redefining the fundamental meaning of play.