Piece is related to Sleeve. Sleeve is related to Jacket. Jacket is related to Upper. 
Glass is related to Eye. Eye is related to Round. Round is related to Twist. 
Piece <--RelatedTo--> Sleeve <--RelatedTo--> Jacket <--RelatedTo--> Upper 
Glass <--RelatedTo--> Eye <--RelatedTo--> Round <--RelatedTo--> Twist 