An event like Notting Hill or Leeds Carnival is much more than a "one-off" day; it takes a whole year of preparation, designing, costume-designing. The steel pan bands, percussion groups, and dance troupes need to form and rehearse. This category is for those permanent groups which have been formed to preserve and develop carnival-related arts, and "perform" them primarily at Carnivals like Notting Hill, but also at other festivals. It may include "mas" bands (from the original Trinidadian idea of masquerade), voluntary groups, community arts/education organisations, and professional companies.