A Prison gang is an inmate organization that operates within a prison system, that has a corporate entity, exists into perpetuity, and whose membership is restrictive, mutually exclusive, and often requires a lifetime commitment. Some prison gangs are transplanted from the street. In some circumstances, prison gangs "outgrow" the internal world of life inside the penitentiary, and go on to engage in criminal activities on the outside. Many prison gangs are racially oriented. Gang umbrella organizations like the Folk Nation and People Nation have originated in prisons.