Elephant is related to Heavy. Heavy is the opposite of Light. Light is a type of Condition. 
Fur is related to Soft. Soft is related to Bed. Sheet can be used for Bed. 
Elephant <--RelatedTo--> Heavy <--Antonym--> Light --IsA--> Condition 
Fur <--RelatedTo--> Soft <--RelatedTo--> Bed <--UsedFor-- Sheet 