Aluminum is a type of Gray. Gray is related to Shade. Shade is related to Variation. Variation is related to Combination. 
Buddy is related to Deputy. Deputy is a type of Assistant. 
Aluminum --IsA--> Gray <--RelatedTo--> Shade <--RelatedTo--> Variation <--RelatedTo--> Combination 
Buddy <--RelatedTo--> Deputy --IsA--> Assistant 