What is "sphereland"

Sphereland: A Fantasy About Curved Spaces and an Expanding Universe is a 1965 novel by Dionys Burger, and is a sequel to Flatland, a novel by "A Square" (a pen name of Edwin Abbott Abbott). The novel expands upon the social and mathematical foundations on which Flatland is based. It is markedly different from the first novel in that it has a more prosaic ending and treatment of society.