Occasion is related to Holiday. Holiday is related to Birthday. Birthday is related to Candle. you are likely to find Candle in/at/on Shelf. 
Mathematics is related to Product. Product is related to Sale. Shoe can be used for Sale. Shoe is related to Tap. 
Occasion <--RelatedTo--> Holiday <--RelatedTo--> Birthday <--RelatedTo--> Candle --AtLocation--> Shelf 
Mathematics <--RelatedTo--> Product <--RelatedTo--> Sale <--UsedFor-- Shoe <--RelatedTo--> Tap 