In his ethnological research, Claude Lévi-Strauss repeatedly observed that the structure of a group as it appears to an outsider does not need to be identical with its actual constitution. For instance, the Bororo of Brazil live in villages where all huts form a circle around a larger house in the middle. This structure obscures the fact that each hut belongs to one of three social groups that are strictly separated from each other by marriage rules. While at first glance the Bororo seem to live in an egalitarian society, their social classes divide them in a way that is similar to the Indian caste system.