Single is related to Item. Item is related to Reward. Reward is related to Type. 
Cell is related to Box. Box can be used for Seat. Seat is related to Airline. 
Single <--RelatedTo--> Item <--RelatedTo--> Reward <--RelatedTo--> Type 
Cell <--RelatedTo--> Box --UsedFor--> Seat <--RelatedTo--> Airline 