Box is related to Mail. 
Horrible is the opposite of Wonderful. Wonderful is a synonym of Fantastic. Fantastic is a different concept from Plain. you are likely to find Plain in/at/on Landscape. 
Box <--RelatedTo--> Mail 
Horrible <--Antonym--> Wonderful <--Synonym--> Fantastic <--DistinctFrom--> Plain --AtLocation--> Landscape 