Pin is related to Safety. Safety is related to Protect. 
Aluminum is a type of Gray. Gray is related to Elephant. Trunk is a type of Elephant. Trunk is related to Feature. 
Pin <--RelatedTo--> Safety <--RelatedTo--> Protect 
Aluminum --IsA--> Gray <--RelatedTo--> Elephant <--IsA-- Trunk <--RelatedTo--> Feature 