equipment is a mean of public with ordered recessive of top / extreme / low
partially_ordered_set is category. fitness_equipment is non_agentive_artifact. sports_equipment is not non_agentive_artifact. sports_equipment is non_agentive_artifact. game_equipment_set is collectable. strict_total_ordering is event_like_ordering. playground_equipment is non_agentive_artifact. stringed_instrument is single_user_device. playground_equipment is not non_agentive_artifact. stringed_instrument is not single_user_device.