Wave is related to Activity. Activity is related to Swimming. River can be used for Swimming. 
Endless is related to Time. Time is a synonym of Clip. Clip is a type of Blow. 
Wave <--RelatedTo--> Activity <--RelatedTo--> Swimming <--UsedFor-- River 
Endless <--RelatedTo--> Time <--Synonym--> Clip --IsA--> Blow 