Wheelchair is derived from Chair. Chair is the opposite of Couch. Couch is related to Tv. Tv is related to Cable. 
Sheep is related to Ball. Ball is related to Object. 
Wheelchair --DerivedFrom--> Chair <--Antonym--> Couch <--RelatedTo--> Tv <--RelatedTo--> Cable 
Sheep <--RelatedTo--> Ball <--RelatedTo--> Object 