Walk is related to Floor. Floor is related to Main. Main is related to Topic. 
Space is related to Park. Park is related to Course. Course is related to Action. Action is related to Stay. 
Walk <--RelatedTo--> Floor <--RelatedTo--> Main <--RelatedTo--> Topic 
Space <--RelatedTo--> Park <--RelatedTo--> Course <--RelatedTo--> Action <--RelatedTo--> Stay 