Pump is related to Gas. Gas is related to Invisible. Invisible is related to Air. 
Representative is similar to Democratic. Democratic is related to Hope. Hope is related to Good. 
Pump <--RelatedTo--> Gas <--RelatedTo--> Invisible <--RelatedTo--> Air 
Representative <--SimilarTo--> Democratic <--RelatedTo--> Hope <--RelatedTo--> Good 