Instrument is related to Used. Used is related to Control. Control is related to Computer. Pc is a type of Computer. 
Law is related to Congress. Congress is related to Politician. Politician is a type of Leader. Superior is a type of Leader. 
Instrument <--RelatedTo--> Used <--RelatedTo--> Control <--RelatedTo--> Computer <--IsA-- Pc 
Law <--RelatedTo--> Congress <--RelatedTo--> Politician --IsA--> Leader <--IsA-- Superior 