Heavy is similar to Big. Big is related to Couch. Couch is a synonym of Frame. 
Alone is related to Self. Self is related to Independent. Independent is a synonym of Main. 
Heavy <--SimilarTo--> Big <--RelatedTo--> Couch <--Synonym--> Frame 
Alone <--RelatedTo--> Self <--RelatedTo--> Independent <--Synonym--> Main 