Iron is related to Type. Type is related to Lamp. Candle is a type of Lamp. 
Tide is related to Phase. Phase is part of Cycle. Cycle is a type of Repeat. 
Iron <--RelatedTo--> Type <--RelatedTo--> Lamp <--IsA-- Candle 
Tide <--RelatedTo--> Phase --PartOf--> Cycle --IsA--> Repeat 