Concentration is a type of Assembly. Concentration is related to Camp. Camp is related to Retreat. 
Pole is related to Area. Area is related to Door. Elevator have Door. Elevator is related to Lift. 
Assembly <--IsA-- Concentration <--RelatedTo--> Camp <--RelatedTo--> Retreat 
Pole <--RelatedTo--> Area <--RelatedTo--> Door <--HasA-- Elevator <--RelatedTo--> Lift 