Ankle is related to Foot. Foot is related to Measure. Proof is a type of Measure. 
Easy is related to Middle. Middle is the opposite of Front. Front is related to Leader. 
Ankle <--RelatedTo--> Foot <--RelatedTo--> Measure <--IsA-- Proof 
Easy <--RelatedTo--> Middle <--Antonym--> Front <--RelatedTo--> Leader 