Swim is related to Example. Example is related to Demonstration. Demonstration is a synonym of Presentation. Presentation is a synonym of Assignment. 
Unhappy is the opposite of Glad. Glad is related to Trash. Trash is related to Trailer. Trailer is related to Sleep. 
Swim <--RelatedTo--> Example <--RelatedTo--> Demonstration <--Synonym--> Presentation <--Synonym--> Assignment 
Unhappy <--Antonym--> Glad <--RelatedTo--> Trash <--RelatedTo--> Trailer <--RelatedTo--> Sleep 