evidence: At the top of the hierarchy were the Brahmins who were mainly teachers and intellectuals and are believed to have come from Brahma's head. Then came the Kshatriyas, or the warriors and rulers, supposedly from his arms. The third slot went to the Vaishyas, or the traders, who were created from his thighs. At the bottom of the heap were the Shudras, who came from Brahma's feet and did all the menial jobs. [...] Rural communities have long been arranged on the basis of castes - the upper and lower castes almost always lived in segregated colonies, the water wells were not shared, Brahmins would not accept food or drink from the Shudras, and one could marry only within one's caste. [...] Despite the obstacles, however, some Dalits and other low-caste Indians, such as BR Ambedkar who authored the Indian constitution, and KR Narayanan who became the nation's first Dalit president, have risen to hold prestigious positions in the country.