The piece appears to represent two twins. They share the same body -which corresponds to the central part of the beaker, rounded in form- and two arms which, as is habitual, are held against the body and lifted towards the central part of the chest. Their long necks are adorned with various strings of necklaces and they also wear bracelets on the wrists. According to the characteristics of the Mambila style, the eyes and mouth are formed by pronounced and prominent ovals. The mouth is open and allows some threatening teeth to be seen. The ears are two circles. This type of recipients are conceived as libation vessels to feed twins and thus inhibit their possible special powers, since for some African cultures it is difficult to understand that a person can be duplicated. Numerous ethnic groups treat twins in a special manner, as though they had supernatural powers and it were necesary to avoid attitudes that may provoke their anger. For some -Dogon, Bamana, Malinke- their birth is a reflection of the original perfection and they are considered to be a reward for the family for its goodness, generosity and welcome. They are usually attributed with the powers of withdoctors, sorcerers or diviners, being situated in a different category from the rest. For other peoples, such as the Yoruba -although during a limited period of time -these births were unlucky events. According to oral tradition, in the kingdom of Oyo these children had to be killed at birth, before the oba received knowledge of their existence. Breaking this customs, the first place where the newborns were permited to live was in the city of Isokum, situated outside the kingdom in the territory of its rival Dahomey. Thus, from approximately the middle of the eighteenth century the birth of twins became a good luck omen. The explanation of these prectices should be sought in the fact that for the Yoruba only animals had multiple births owing to their promiscuity, therefore: "The births of twins among human beings was a sign of loose morals, and the purpose of the infanticide was therefore to resolve a problem of a moral nature".