Sea can be Wet. Wet is the opposite of Beautiful. Beautiful is a different concept from Nasty. 
System is related to Door. Door is related to Opening. Opening is a synonym of Gap. Gap is related to Distance. 
Sea --HasProperty--> Wet <--Antonym--> Beautiful <--DistinctFrom--> Nasty 
System <--RelatedTo--> Door <--RelatedTo--> Opening <--Synonym--> Gap <--RelatedTo--> Distance 