Roof is a synonym of Ceiling. Ceiling is a synonym of Cap. Cap is related to Safety. 
Strong is related to Iron. you are likely to find Iron in/at/on Kitchen. you are likely to find Chef in/at/on Kitchen. 
Roof <--Synonym--> Ceiling <--Synonym--> Cap <--RelatedTo--> Safety 
Strong <--RelatedTo--> Iron --AtLocation--> Kitchen <--AtLocation-- Chef 