Christmas is related to Snow. Snow is related to Liquid. Liquid is related to Solution. 
Excitement is related to Surprise. Surprise is related to Celebration. Ball is a type of Celebration. Ball is related to String. 
Christmas <--RelatedTo--> Snow <--RelatedTo--> Liquid <--RelatedTo--> Solution 
Excitement <--RelatedTo--> Surprise <--RelatedTo--> Celebration <--IsA-- Ball <--RelatedTo--> String 