Theme is related to Park. Park is a synonym of Common. Common is related to Steel. 
Land is related to Road. Road is related to Bridge. Bridge is related to Structure. Housing is a type of Structure. 
Theme <--RelatedTo--> Park <--Synonym--> Common <--RelatedTo--> Steel 
Land <--RelatedTo--> Road <--RelatedTo--> Bridge <--RelatedTo--> Structure <--IsA-- Housing 